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Ладно, на сегодня хватит, даже можно сказать полезно-активный GMAT день был.
GMAT 700все кто сдавал или будет сдавать сие чудесный тест
Автор crosswall, 19.06.2008, 10:56
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#742
Отправлено 23.01.2009, 22:50:46
crosswall
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- Свой человек
- 529 сообщений
to our lovely Kasatka and many other GreenPeacer 
for next time
Between June 1987 and May 1988, the bodies of at least 740 bottlenose dolphins out of a total coastal population of 3,000 to 5,000 washed ashore on the Atlantic coast of the United States. Since some of the dead animals never washed ashore, the overall disaster was presumably worse; perhaps 50 percent of the population died. A dolphin die-off of this character and magnitude had never before been observed; furthermore, the dolphins exhibited a startling range of symptoms. The research team that examined the die-off noted the presence of both skin lesions and internal lesions in the liver, lung, pancreas and heart, which suggested a massive opportunistic bacterial infection of already weakened animals.
Tissues from the stricken dolphins were analyzed for a variety of toxins. Brevetoxin, a toxin produced by the blooming of the alga Ptychodiscus brevis, was present in eight out of seventeen dolphins tested. Tests for synthetic pollutants revealed that polychlorinated biphenyls (PCBs) were present in almost all animals tested.
The research team concluded that brevetoxin poisoning was the most likely cause of the illnesses that killed the dolphins. Although P. brevis is ordinarily not found along the Atlantic coast, an unusual bloom of this organism—such blooms are called “red tides” because of the reddish color imparted by the blooming algae—did occur in the middle of the affected coastline in October 1987. These researchers believe the toxin accumulated in the tissue of fish and then was ingested by dolphins that preyed on them. The emaciated appearance of many dolphins indicated that they were metabolizing their blubber reserves, thereby reducing their buoyancy and insulation (and adding to overall stress) as well as releasing stores of previously accumulated synthetic pollutants, such as PCBs, which further exacerbated their condition. The combined impact made the dolphins vulnerable to opportunistic bacterial infection, the ultimate cause of death.
For several reasons, however, this explanation is not entirely plausible. First, bottlenose dolphins and P. brevis red tides are both common in the Gulf of Mexico, yet no dolphin die-off of a similar magnitude has been noted there. Second, dolphins began dying in June, hundreds of miles north of and some months earlier than the October red tide bloom. Finally, the specific effects of brevetoxin on dolphins are unknown, whereas PCB poisoning is known to impair functioning of the immune system and liver and to cause skin lesions; all of these problems are observed in the diseased animals. An alternative hypothesis, which accounts for these facts, is that a sudden influx of pollutants, perhaps from offshore dumping, triggered a cascade of disorders in animals whose systems were already heavily laden with pollutants. Although brevetoxin may have been a contributing factor, the event that actually precipitated the die-off was a sharp increase in the dolphins’ exposure to synthetic pollutants.
14. The passage is primarily concerned with assessing
(A) the effects of a devastating bacterial infection in Atlantic coast bottlenose dolphins
(B) the progress by which illnesses in Atlantic coast bottlenose dolphins were correctly diagnosed
(С) the weaknesses in the research methodology used to explore the dolphin die-off
(D) possible alternative explanations for the massive dolphin die-off
(E) relative effects of various marine pollutants on dolphin mortality
15. Which one of the following is mentioned in the passage as evidence for the explanation of the dolphin die-off offered in the final paragraph?
(A) the release of stored brevetoxins from the dolphins’ blubber reserves
(B) the date on which offshore dumping was known to have occurred nearby
(С) the presence of dumping sites for PCBs in the area
(D) the synthetic pollutants that were present in the fish eaten by the dolphins
(E) the effects of PCBs on liver function in dolphins
16. Which one of the following is most analogous to the approach taken by author of the passage with regard to the research described in the third paragraph?
(A) A physics teacher accepts the data from a student’s experiment but questions the student’s conclusions.
(B) An astronomer provides additional observations to support another astronomer’s theory.
(С) A cook revises a traditional recipe by substituting modern ingredients for those used in the original.
(D) A doctor prescribes medication for a patient whose illness was misdiagnosed by another doctor.
(E) A microbiologist sets out to replicate the experiment that yielded a classic theory of cell structure.
17. Which one of the following most accurately describes the organization of the last paragraph?
(A) One explanation is criticized and different explanation is proposed.
(B) An argument is advanced and then refuted by means of an opposing argument.
(С) Objections against a hypothesis are advanced, the hypothesis is explained more fully, and then the objections are rejected.
(D) New evidence in favor of a theory is described, and then the theory is reaffirmed.
(E) Discrepancies between two explanations are noted, and a third explanation is proposed.
18. It can be inferred from the passage that the author would most probably agree with which one of the following statements about brevetoxin?
(A) It may have been responsible for the dolphins’ skin lesions but could not have contributed to the bacterial infection.
(B) It forms more easily when both P. brevis and synthetic pollutants are present in the environment simultaneously.
(С) It damages liver function and immune system responses in bottlenose dolphins but may not have triggered this particular dolphin die-off.
(D) It is unlikely to be among the factors that contributed to the dolphin die-off.
(E) It is unlikely to have caused the die-off because it was not present in the dolphins’ environment when the die-off began.
19. The explanation for the dolphin die-off given by the research team most strongly supports which one of the following?
(A) The biological mechanism by which brevetoxin affects dolphins is probably different from that by which it affects other marine animals.
(B) When P. brevis blooms in an area where it does not usually exist, it is more toxic than it is in its usual habitat.
(С) Opportunistic bacterial infection is usually associated with brevetoxin poisoning in bottlenose dolphins.
(D) The dolphins’ emaciated state was probably a symptom of PCB poisoning rather than of brevetoxin poisoning.
(E) When a dolphin metabolizes its blubber, the PCBs released may be more dangerous to the dolphin than they were when stored in the blubber.
20. The author refers to dolphins in the Gulf of Mexico in the last paragraph in order to
(A) refute the assertion that dolphins tend not to inhabit areas where P. brevis is common
(B) compare the effects of synthetic pollutants on these dolphins and on Atlantic coast dolphins
(С) cast doubt on the belief that P. brevis contributes substantially to dolphin die-offs
(D) illustrate the fact that dolphins in relatively pollution-free waters are healthier than dolphins in polluted waters
(E) provide evidence for the argument that P. brevis was probably responsible for the dolphins’ deaths
21. Which one of the following factors is explicitly cited as contributing to the dolphins’ deaths in both theories discussed in the passage?
(A) the dolphins’ diet
(B) the presence of P. brevis in the Gulf of Mexico
(С) the wide variety of toxins released by the red tide bloom of October 1987
(D) the presence of synthetic pollutants in the dolphins’ bodies
(E) the bacterial infection caused by a generalized failure of the dolphins’ immune systems
for next timeBetween June 1987 and May 1988, the bodies of at least 740 bottlenose dolphins out of a total coastal population of 3,000 to 5,000 washed ashore on the Atlantic coast of the United States. Since some of the dead animals never washed ashore, the overall disaster was presumably worse; perhaps 50 percent of the population died. A dolphin die-off of this character and magnitude had never before been observed; furthermore, the dolphins exhibited a startling range of symptoms. The research team that examined the die-off noted the presence of both skin lesions and internal lesions in the liver, lung, pancreas and heart, which suggested a massive opportunistic bacterial infection of already weakened animals.
Tissues from the stricken dolphins were analyzed for a variety of toxins. Brevetoxin, a toxin produced by the blooming of the alga Ptychodiscus brevis, was present in eight out of seventeen dolphins tested. Tests for synthetic pollutants revealed that polychlorinated biphenyls (PCBs) were present in almost all animals tested.
The research team concluded that brevetoxin poisoning was the most likely cause of the illnesses that killed the dolphins. Although P. brevis is ordinarily not found along the Atlantic coast, an unusual bloom of this organism—such blooms are called “red tides” because of the reddish color imparted by the blooming algae—did occur in the middle of the affected coastline in October 1987. These researchers believe the toxin accumulated in the tissue of fish and then was ingested by dolphins that preyed on them. The emaciated appearance of many dolphins indicated that they were metabolizing their blubber reserves, thereby reducing their buoyancy and insulation (and adding to overall stress) as well as releasing stores of previously accumulated synthetic pollutants, such as PCBs, which further exacerbated their condition. The combined impact made the dolphins vulnerable to opportunistic bacterial infection, the ultimate cause of death.
For several reasons, however, this explanation is not entirely plausible. First, bottlenose dolphins and P. brevis red tides are both common in the Gulf of Mexico, yet no dolphin die-off of a similar magnitude has been noted there. Second, dolphins began dying in June, hundreds of miles north of and some months earlier than the October red tide bloom. Finally, the specific effects of brevetoxin on dolphins are unknown, whereas PCB poisoning is known to impair functioning of the immune system and liver and to cause skin lesions; all of these problems are observed in the diseased animals. An alternative hypothesis, which accounts for these facts, is that a sudden influx of pollutants, perhaps from offshore dumping, triggered a cascade of disorders in animals whose systems were already heavily laden with pollutants. Although brevetoxin may have been a contributing factor, the event that actually precipitated the die-off was a sharp increase in the dolphins’ exposure to synthetic pollutants.
14. The passage is primarily concerned with assessing
(A) the effects of a devastating bacterial infection in Atlantic coast bottlenose dolphins
(B) the progress by which illnesses in Atlantic coast bottlenose dolphins were correctly diagnosed
(С) the weaknesses in the research methodology used to explore the dolphin die-off
(D) possible alternative explanations for the massive dolphin die-off
(E) relative effects of various marine pollutants on dolphin mortality
15. Which one of the following is mentioned in the passage as evidence for the explanation of the dolphin die-off offered in the final paragraph?
(A) the release of stored brevetoxins from the dolphins’ blubber reserves
(B) the date on which offshore dumping was known to have occurred nearby
(С) the presence of dumping sites for PCBs in the area
(D) the synthetic pollutants that were present in the fish eaten by the dolphins
(E) the effects of PCBs on liver function in dolphins
16. Which one of the following is most analogous to the approach taken by author of the passage with regard to the research described in the third paragraph?
(A) A physics teacher accepts the data from a student’s experiment but questions the student’s conclusions.
(B) An astronomer provides additional observations to support another astronomer’s theory.
(С) A cook revises a traditional recipe by substituting modern ingredients for those used in the original.
(D) A doctor prescribes medication for a patient whose illness was misdiagnosed by another doctor.
(E) A microbiologist sets out to replicate the experiment that yielded a classic theory of cell structure.
17. Which one of the following most accurately describes the organization of the last paragraph?
(A) One explanation is criticized and different explanation is proposed.
(B) An argument is advanced and then refuted by means of an opposing argument.
(С) Objections against a hypothesis are advanced, the hypothesis is explained more fully, and then the objections are rejected.
(D) New evidence in favor of a theory is described, and then the theory is reaffirmed.
(E) Discrepancies between two explanations are noted, and a third explanation is proposed.
18. It can be inferred from the passage that the author would most probably agree with which one of the following statements about brevetoxin?
(A) It may have been responsible for the dolphins’ skin lesions but could not have contributed to the bacterial infection.
(B) It forms more easily when both P. brevis and synthetic pollutants are present in the environment simultaneously.
(С) It damages liver function and immune system responses in bottlenose dolphins but may not have triggered this particular dolphin die-off.
(D) It is unlikely to be among the factors that contributed to the dolphin die-off.
(E) It is unlikely to have caused the die-off because it was not present in the dolphins’ environment when the die-off began.
19. The explanation for the dolphin die-off given by the research team most strongly supports which one of the following?
(A) The biological mechanism by which brevetoxin affects dolphins is probably different from that by which it affects other marine animals.
(B) When P. brevis blooms in an area where it does not usually exist, it is more toxic than it is in its usual habitat.
(С) Opportunistic bacterial infection is usually associated with brevetoxin poisoning in bottlenose dolphins.
(D) The dolphins’ emaciated state was probably a symptom of PCB poisoning rather than of brevetoxin poisoning.
(E) When a dolphin metabolizes its blubber, the PCBs released may be more dangerous to the dolphin than they were when stored in the blubber.
20. The author refers to dolphins in the Gulf of Mexico in the last paragraph in order to
(A) refute the assertion that dolphins tend not to inhabit areas where P. brevis is common
(B) compare the effects of synthetic pollutants on these dolphins and on Atlantic coast dolphins
(С) cast doubt on the belief that P. brevis contributes substantially to dolphin die-offs
(D) illustrate the fact that dolphins in relatively pollution-free waters are healthier than dolphins in polluted waters
(E) provide evidence for the argument that P. brevis was probably responsible for the dolphins’ deaths
21. Which one of the following factors is explicitly cited as contributing to the dolphins’ deaths in both theories discussed in the passage?
(A) the dolphins’ diet
(B) the presence of P. brevis in the Gulf of Mexico
(С) the wide variety of toxins released by the red tide bloom of October 1987
(D) the presence of synthetic pollutants in the dolphins’ bodies
(E) the bacterial infection caused by a generalized failure of the dolphins’ immune systems
#744
Отправлено 24.01.2009, 02:13:52
Snare
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эхх, зарекался дома сидеть не гулять.. но пятница! как это вы классно придумали с белыми чернилами, прям письма Ленина молоком на полях газет 
. я в детстве так писал а потом утюгом или свечкой снизу, и чудеса творились. но детство уже давно позади, и вокруг суровые реалии недетской жизни одна из которых ЖИМАТ!!
итак, сообщаю выйгрышные номера лотереи:
********************************************
PS - 1D легко, за него вам 0,1 очков
2B! очень хитрый вопрос который надо разобрать на примере crosswall который ошибся два раза
ошибка 1: он, как и я все нормальные люди, умножил 4 недели на 12 месяцев, полученные 48 умножил на 10 и вычел оттуда 12*30, и у него вместо 480-360=120 получилось 220 так как он скорей всего смотрел только на десятки в возможных ответах
ошибка 2: он, как и я все нормальные люди, не подозревал что в году не 48, а целых 52 недели, и что ответ таким образом (В) 160. отсюда вопрос: обязан ли ДЖМАТовец знать такие тонкости или это некорректный вопрос? на всякий случай запомните этот момент.
ну и далее легко: 3C 4A 5E но вопрос мы признали неправильным 6B 7B 8A 9C 10A - спасибо crosswall за методику решения
********************************************
SC - CBDDABBDEA (crosswall - 2 incorrect, Kasatka - 3 incorrect)
********************************************
TOTAL SCORE: crosswall 797 (Q59V58), Kasatka 797 (Q60V57)
Your results have been sent to you and all top-tier business schools of Mozambique via pigeon mail
. я в детстве так писал а потом утюгом или свечкой снизу, и чудеса творились. но детство уже давно позади, и вокруг суровые реалии недетской жизни одна из которых ЖИМАТ!!итак, сообщаю выйгрышные номера лотереи:
********************************************
PS - 1D легко, за него вам 0,1 очков
2B! очень хитрый вопрос который надо разобрать на примере crosswall который ошибся два раза
ошибка 1: он, как и я все нормальные люди, умножил 4 недели на 12 месяцев, полученные 48 умножил на 10 и вычел оттуда 12*30, и у него вместо 480-360=120 получилось 220 так как он скорей всего смотрел только на десятки в возможных ответах
ошибка 2: он, как и я все нормальные люди, не подозревал что в году не 48, а целых 52 недели, и что ответ таким образом (В) 160. отсюда вопрос: обязан ли ДЖМАТовец знать такие тонкости или это некорректный вопрос? на всякий случай запомните этот момент.
ну и далее легко: 3C 4A 5E но вопрос мы признали неправильным 6B 7B 8A 9C 10A - спасибо crosswall за методику решения
********************************************
SC - CBDDABBDEA (crosswall - 2 incorrect, Kasatka - 3 incorrect)
********************************************
TOTAL SCORE: crosswall 797 (Q59V58), Kasatka 797 (Q60V57)
Your results have been sent to you and all top-tier business schools of Mozambique via pigeon mail
#745
Отправлено 24.01.2009, 08:21:39
crosswall
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- Свой человек
- 529 сообщений
Честно говоря нет, просто ошибка по невнимательности2B! очень хитрый вопрос который надо разобрать на примере crosswall который ошибся два раза
ошибка 1: он, как и я все нормальные люди, умножил 4 недели на 12 месяцев, полученные 48 умножил на 10 и вычел оттуда 12*30, и у него вместо 480-360=120 получилось 220 так как он скорей всего смотрел только на десятки в возможных ответах
ошибка 2: он, как и я все нормальные люди, не подозревал что в году не 48, а целых 52 недели, и что ответ таким образом (В) 160. отсюда вопрос: обязан ли ДЖМАТовец знать такие тонкости или это некорректный вопрос? на всякий случай запомните этот момент.
я знаю, что в месяце не ровно 4 недели и что месяцы разной длины, поэтому я 365 дней разделил на 7, ответ в уме считается - 52 недели и один день. Ошибся когда от 520 отнимал 360. Сделал это в уме, но ошибся.
Увы, но такие ошибки гудят нас, т.к. задача простая, но если ты её не решишь, то тебя тест накажет. Прочем, мне горазно интересней ответы по Verbal!!!
#746
Отправлено 24.01.2009, 11:15:56
Snare
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- В доску свой
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а вот вам хитренький вопрос на CR с элементами RC и PS который я написал эксклюзивно для вас и под вас. первая попытка, не судите строго 
Figures show that during 5 recent years, the average GMAT score has been gradually lowering worldwide. Since GMAT takers represent MBA applicants, this fact leads to decreased competition per MBA place, and therefore increases chances for applicants scored near average to be enrolled this year.
Which of the following most seriously undermines the conclusion drawn?
(a) GMAT score is just one of the important admission criteria
(b) In certain parts of the world, the average GMAT score has lowered less than in the others
© The average score is not a representative figure without median (mean) score and combined percentile
(d) While the average GMAT score has been lowering, the pool of test-takers has been rising
(e) GMAT takers may use their scores for other purposes than applying for MBA
Figures show that during 5 recent years, the average GMAT score has been gradually lowering worldwide. Since GMAT takers represent MBA applicants, this fact leads to decreased competition per MBA place, and therefore increases chances for applicants scored near average to be enrolled this year.
Which of the following most seriously undermines the conclusion drawn?
(a) GMAT score is just one of the important admission criteria
(b) In certain parts of the world, the average GMAT score has lowered less than in the others
© The average score is not a representative figure without median (mean) score and combined percentile
(d) While the average GMAT score has been lowering, the pool of test-takers has been rising
(e) GMAT takers may use their scores for other purposes than applying for MBA
Сообщение отредактировал Snare: 24.01.2009, 11:17:36
#749
Отправлено 27.01.2009, 18:44:48
Kasatka
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- Постоялец
- 482 сообщений
Почему тишина? Все забили на GMAT что ли?
Решила буду пересдавать в конце весны. Буду сначала все перечитывать и решать.
Но честно сказать уже отчаялась, трудно дается RC.
to Snare:
© The average score is not a representative figure without median (mean) score and combined percentile
Решила буду пересдавать в конце весны. Буду сначала все перечитывать и решать.
Но честно сказать уже отчаялась, трудно дается RC.
to Snare:
© The average score is not a representative figure without median (mean) score and combined percentile
Сообщение отредактировал Kasatka: 27.01.2009, 18:45:15
#750
Отправлено 27.01.2009, 19:09:00
Snare
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тоже хотел спросить, куда подевались все акулы и касатки бизнеса? 
я не то чтобы забил - отвлекся на выходные. кстати, так и не нашел нигде разбор вероятностей и комбинаторики на примерах.
сегодня на работе третий пробник заскорил на 640 q43v36. эхх, сохранить бы такой стабильный 20pts/week progress rate до реального теста уже в эту пятницу
а по моему CR - я ващето (D) имел ввиду, но щас смотрю - и А и С подходять в принципе. вот такой у меня суперский CR получился
я не то чтобы забил - отвлекся на выходные. кстати, так и не нашел нигде разбор вероятностей и комбинаторики на примерах.сегодня на работе третий пробник заскорил на 640 q43v36. эхх, сохранить бы такой стабильный 20pts/week progress rate до реального теста уже в эту пятницу
а по моему CR - я ващето (D) имел ввиду, но щас смотрю - и А и С подходять в принципе. вот такой у меня суперский CR получился
#752
Отправлено 28.01.2009, 14:53:03
Snare
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давайте вместе разберем пробные вопросы в которых я запарился:
1. if 5 /\ (степень) 21 * 4 /\ 11 = 2 * 10 /\ n, what is the value of n?
A11 B21 C22 D23 E32
как привести обе части в один вид чтобы работать только со степенями?
2. for every positive integer n, functioh h(n) is defined as product of all even integers from 2 to n. if p is a smallest prime factor of h(100)+1, then p is:
A between 2 & 10
B between 10 & 20
C between 20 & 30
D between 30 & 40
E greater that 40
ваще не перевариваю такие задачи на number properties
3. тоже самое, я угадал но не понял как: if n is a positive integer and the product of all integers from 1 to n inclusive is 990, what is the least value of n?
A10 B11 C21 D13 E14
4. if 75 can be written as sum of squares of 3 different positive integers, what is the sum of these integers?
A17 B16 C15 D14 E13
5. DS: id integer x divisible by 6?
(1) x+3 divisible by 3
(2) x+3 is odd
6. DS: at what 2 points does graph y=(x+a)(x+b) intersect x-axis?
(1) a+b = -1
(2) y-interscept is (0, -6)
7. amount per day_____ 48__70__80__84__96
number of days________2____3___4____7___4
form table above, what is the median amount per day earned for total 20 days?
8. You are to select 2 tables and 2 chairs from a warehouse that different from each other. If there are 5 chairs there and 150 combinations possible, how many tables are there?
A6 B8 C10 D15 E30
9. DS: of 800 sweaters 150 are red. How many of red sweaters are woolen?
(1) 320 are neither red nor woolen
(2) 100 of the red are not woolen
10. DS: A, P and M shared driving for 1500 miles. Which of them drove largest distance?
(1) A drove 1 hr longer but 5 mph slower than P
(2) M drove 9 hrs and averaged 50 mph
11. If d is standard deviation of x,y,z what is st.deviation of x+5,y+5,z+5?
Ad B3d C15d Dd+5 Ed+15
жду ваших мнений asap
1. if 5 /\ (степень) 21 * 4 /\ 11 = 2 * 10 /\ n, what is the value of n?
A11 B21 C22 D23 E32
как привести обе части в один вид чтобы работать только со степенями?
2. for every positive integer n, functioh h(n) is defined as product of all even integers from 2 to n. if p is a smallest prime factor of h(100)+1, then p is:
A between 2 & 10
B between 10 & 20
C between 20 & 30
D between 30 & 40
E greater that 40
ваще не перевариваю такие задачи на number properties
3. тоже самое, я угадал но не понял как: if n is a positive integer and the product of all integers from 1 to n inclusive is 990, what is the least value of n?
A10 B11 C21 D13 E14
4. if 75 can be written as sum of squares of 3 different positive integers, what is the sum of these integers?
A17 B16 C15 D14 E13
5. DS: id integer x divisible by 6?
(1) x+3 divisible by 3
(2) x+3 is odd
6. DS: at what 2 points does graph y=(x+a)(x+b) intersect x-axis?
(1) a+b = -1
(2) y-interscept is (0, -6)
7. amount per day_____ 48__70__80__84__96
number of days________2____3___4____7___4
form table above, what is the median amount per day earned for total 20 days?
8. You are to select 2 tables and 2 chairs from a warehouse that different from each other. If there are 5 chairs there and 150 combinations possible, how many tables are there?
A6 B8 C10 D15 E30
9. DS: of 800 sweaters 150 are red. How many of red sweaters are woolen?
(1) 320 are neither red nor woolen
(2) 100 of the red are not woolen
10. DS: A, P and M shared driving for 1500 miles. Which of them drove largest distance?
(1) A drove 1 hr longer but 5 mph slower than P
(2) M drove 9 hrs and averaged 50 mph
11. If d is standard deviation of x,y,z what is st.deviation of x+5,y+5,z+5?
Ad B3d C15d Dd+5 Ed+15
жду ваших мнений asap
#754
Отправлено 28.01.2009, 18:21:05
Kasatka
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- 482 сообщений
давайте вместе разберем пробные вопросы в которых я запарился:
9. DS: of 800 sweaters 150 are red. How many of red sweaters are woolen?
(1) 320 are neither red nor woolen
(2) 100 of the red are not woolen
Лично мне проще и быстрее дается когда я рисую табличку.
Не вставляются здесь таблички, попробуй нарисуй: три столбца (Red, Not Red, Total) и три строки (Woolen, Not Woolen, Total) и вставляешь в нее данные и проверяешь какие условия подходят.
Можно посчитать конечно.
Логически/математически: всего 800 свитеров, 150 R, 650 NR. нужно найти R&W
1) условие нам дает что 320 NR&NW, 330 NR&W, а R&W неизвестно
2) Total 150 Red - 100 R&NW = 50 R&W, т.е. условие само по себе достаточное
скоро вернусь
Сообщение отредактировал Kasatka: 28.01.2009, 18:23:21
#755
Отправлено 28.01.2009, 19:52:13
Kasatka
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7. amount per day_____ 48__70__80__84__96
number of days________2____3___4____7___4
form table above, what is the median amount per day earned for total 20 days?
20 дней, значит median равно среднему значению 10-го и 11-го дней, т.е. 84
#756
Отправлено 28.01.2009, 20:00:04
Kasatka
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5. DS: id integer x divisible by 6?
(1) x+3 divisible by 3
(2) x+3 is odd
1) X может быть равно 9 or 12 etc. NS;
2) X может быть равно 8 or 12 NS;
если в условии не сказано что X не равно 0, то вместе оба условия NS.
10. DS: A, P and M shared driving for 1500 miles. Which of them drove largest distance?
(1) A drove 1 hr longer but 5 mph slower than P
(2) M drove 9 hrs and averaged 50 mph
ни одно условие само по себе и оба условия вместе - NS
со второго условия мы знаем что М проехал 450, но сколько проехали A & P я не смогла вычислить.
#757
Отправлено 28.01.2009, 20:55:12
Snare
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правильный ответ. но как мы вычислили именно 10й и 11й дни? ведь строка days не дает хронологии20 дней, значит median равно среднему значению 10-го и 11-го дней, т.е. 84
7. amount per day_____ 48__70__80__84__96
number of days________2____3___4____7___4
form table above, what is the median amount per day earned for total 20 days?
#759
Отправлено 29.01.2009, 11:17:47
Kasatka
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правильный ответ. но как мы вычислили именно 10й и 11й дни? ведь строка days не дает хронологии
20 дней, значит median равно среднему значению 10-го и 11-го дней, т.е. 84
7. amount per day_____ 48__70__80__84__96
number of days________2____3___4____7___4
form table above, what is the median amount per day earned for total 20 days?
Смотри у тебя в условии написано, что 2 дня amount был по 48, 3 дня по 70.
Выстраиваешь по возрастающей
1) 48
2) 48
3) 70
4) 70
5) 70...
10) 84
11) 84..
20) 96
или еще проще, у тебя уже стоит по возрастающей, смотришь дни 2+3+4=9, т.е. стопудово 10-ый и 11-ый дни выпадают по 84.
надеюсь понятно, по другому не умею объяснять.
#760
Отправлено 30.01.2009, 13:05:07
crosswall
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привет!
Аймбак. Snare, я так понимаю уже приближается к концу реального теста. Удачи ему!
Касательно задачи
В сущности речь тут "functioh h(n) is defined as product of all even integers from 2 to n" идет о факториале целых чисел от 2 до n.
Допустим что n=4, тогда h(4) = 2*3*4. Тогда h(4) + 1 = 2*3*4 + 1
Теперь посмотрим что является делителем числа 2*3*4 + 1. Это 1 конечно, но не 2, не 3, не 4, т.к. есть "+1", и есть такая особенность что если в сумме чисел одно число делится нацело, а второе слагаемое нет, то и сумма итоговая не делится. Пример - (10 + 6)/5 - 10 на 5 делится, а 6 на 5 без остатка не делится. Конечно вы можете сказать, что 10 делится на 5 и может быть записано так (6+4)/5. А при этом ни 6 ни 4 не делится на 5. Это правда. НО мы говорим про случай когда одно слагаемое делится (10/5), а второе нет (6/5). Формулируем теорему - если одно слагаемое делится нацело, а второе не делится нацело, то и сумма не делится нацело. А если и первое слагаемое и второе слаемое делится, то и сумма делится (это очевидно, по моему мнению).
ОК, возвращаемся к задаче. Видим 2*3*4 + 1. Понимаем что сумма делится на 1 (но 1 - это не prime), и на какое-то число >4.
Продолжаем аналогию,но уже для h(100) + 1 = 2*3*4*5*...*99*100 + 1. Ответ - ближайщий prime делитель больше 100.
Вопрос может возникнуть следующий - зачем речь идет именно о prime делителе. Надеюсь, что вы сами догадаетесь
P.S. Ответ Е, если что
Аймбак. Snare, я так понимаю уже приближается к концу реального теста. Удачи ему!
Касательно задачи
Интересная задача, я её в общем в первый раз угадал логически помыслив, а потом узнал решение. Вот оно2. for every positive integer n, functioh h(n) is defined as product of all even integers from 2 to n. if p is a smallest prime factor of h(100)+1, then p is:
A between 2 & 10
B between 10 & 20
C between 20 & 30
D between 30 & 40
E greater that 40
ваще не перевариваю такие задачи на number properties
В сущности речь тут "functioh h(n) is defined as product of all even integers from 2 to n" идет о факториале целых чисел от 2 до n.
Допустим что n=4, тогда h(4) = 2*3*4. Тогда h(4) + 1 = 2*3*4 + 1
Теперь посмотрим что является делителем числа 2*3*4 + 1. Это 1 конечно, но не 2, не 3, не 4, т.к. есть "+1", и есть такая особенность что если в сумме чисел одно число делится нацело, а второе слагаемое нет, то и сумма итоговая не делится. Пример - (10 + 6)/5 - 10 на 5 делится, а 6 на 5 без остатка не делится. Конечно вы можете сказать, что 10 делится на 5 и может быть записано так (6+4)/5. А при этом ни 6 ни 4 не делится на 5. Это правда. НО мы говорим про случай когда одно слагаемое делится (10/5), а второе нет (6/5). Формулируем теорему - если одно слагаемое делится нацело, а второе не делится нацело, то и сумма не делится нацело. А если и первое слагаемое и второе слаемое делится, то и сумма делится (это очевидно, по моему мнению).
ОК, возвращаемся к задаче. Видим 2*3*4 + 1. Понимаем что сумма делится на 1 (но 1 - это не prime), и на какое-то число >4.
Продолжаем аналогию,но уже для h(100) + 1 = 2*3*4*5*...*99*100 + 1. Ответ - ближайщий prime делитель больше 100.
Вопрос может возникнуть следующий - зачем речь идет именно о prime делителе. Надеюсь, что вы сами догадаетесь
P.S. Ответ Е, если что
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