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S E 3 weeks ago Data Sufficiency |

Data Sufficiency (more)

How much time did it take a certain car to travel 400 kilometers?  (1) The car traveled the first 200 kilometers in 2.5 hours  (2) If the car’s average speed had been 20 kilometers per hour greater than it was, it would have traveled the 400 kilometers in 1 hours less time than it did

Statement 1 - The car traveled the first 200 kilometers in 2.5 hours

Insufficient because the speed of the car may change between 200 and 400 km

 

Statement 2 -

Assume the average speed of the car for 400 kms be s and time taken be t

s = 400/t    (Since speed = distance / time) ... (1)

When time = t - 1, speed = s+20

s + 20 = 400 / (t - 1)

from equation (1)

400/t  + 20 = 400 / (t - 1)

400 (t - 1) + 20 t (t - 1) = 400 t

400t - 400 + 20t2 - 20t = 400t

20t2 - 20t - 400 = 0

t2 - t - 20 = 0

t2 - 5t + 4t - 20 = 0

t (t - 5) + 4 (t - 5) = 0

(t - 5) (t + 4) = 0

t = - 5 or t = 4 hours

t = -5 is not possible hence

t = 4 hours

Sufficient.

 

 

Recently discovered fossil remains strongly suggest that the Australian egg-laying mammals of today are a branch of the main stem of mammalian evolution rather than developing independently from a common ancestor of mammals more than 220 million years ago (more)

Recently discovered fossil remains strongly suggest that the Australian egg-laying mammals of today are a branch of the main stem of mammalian evolution rather than developing independently from a common ancestor of mammals more than 220 million years ago.

(A) rather than developing independently from
(B) rather than a type that developed independently from
(C) rather than a type whose developments was independent of
(D) instead of developing independently from
(E) instead of a development that was independent of

 

The two splits here are rather and instead. Rather is more appropriate to use in this text. Instead means an alternative and in the context of the sentence, it is not an alternative being referred to. Hence we eliminate answer choices D and E. Answer choice C is wordy. Answer choice B is correct as it clearly conveys the distinction and uses the word 'type' to make the text more specific. 

Being a United States citizen since 1988 and born in Calcutta in 1940, author Bharati Mukherjee has lived in England and Canada, and first came to the United States in 1961 to study at the Iowa Writers' Workshop. (more)

Being a United States citizen since 1988 and born in Calcutta in 1940, author Bharati Mukherjee has lived in England and Canada, and first came to the United States in 1961 to study at the Iowa Writers' Workshop.

(A) Being a United States citizen since 1988 and born in Calcutta in 1940, author Bharati Mukherjee has
(B) Having been a United States citizen since 1988, she was born in Calcutta in 1940; author Bharati Mukherjee
(C) Born in Calcutta in 1940, author Bharati Mukherjee became a United States citizen in 1988; she has
(D) Being born in Calcutta in 1940 and having been a United States citizen since 1988, author Bharati Mukherjee
(E) Having been born in Calcutta in 1940 and being a United States citizen since 1988, author Bharati Mukherjee

Answer choice C is the correct one as it introduces the subject right after the first description. It very simply conveys the series of events of the subjects life and uses the correct tense to convey the meaning. Answer choice B, D, and E use incorrect tense at the start of the sentence. Compared to answer choice A, answer choice C is more precise and hence the right one. 

Which of the following pieces of information, if true, weakens the conclusion above? (more)

Experts estimate that insurance companies' tardiness in paying doctors for legitimate medical claims adds approximately 10 percent in overhead costs for physicians. Insurance companies counter that the tardiness sometimes results from billing errors made by the doctors themselves. Since dealing with these billing errors costs the insurance companies time and money, it is clear that insurance companies do not have a significant economic incentive to delay claim payments to doctors.

Which of the following pieces of information, if true, weakens the conclusion above?

a) Some doctors who submit accurate bills to insurance companies still receive tardy payments.
b) The cost to the insurance companies to process incorrect bills from doctors' offices is roughly equivalent to the increased costs that physicians accrue as a result of tardy payments from insurance companies.
c) A rising proportion of medical claims submitted by doctors to insurance companies are deemed illegitimate by those insurance companies.
d) The billing errors made by doctors' offices are typically very minor, such as the submission of a claim with an outdated patient home address.
e) The overhead costs incurred by doctors as a result of delayed insurance payments result in an increase in the premiums paid by consumers to health insurance companies that far exceed any increase in the fees paid to doctors by insurance companies.

The conclusion of the passage is that the insurance companies' do not have an economic advantage in delaying doctors medical claims payments. As delaying the payments costs the insurance companies time and money, there is no incentive for the companies for being tardy. We need to choose an answer choice which contrasts this conclusion and shows that the insurance companies indeed have an advantage in delaying the claim payments to doctors.
a) This answer choice doesn't point to insurance companies making a profit, it just shows that the company is tardy even though the claim bills are being submitted on time.
b) This answer choice also does not tell us if the insurance companies are making any profits.
c) This answer choice is irrelevant with regards to the context of the question
d) This answer choice is also irrelevant
e) This is the correct answer choice as it clearly shows that overhead costs that the doctors incur due to delayed claims payments, far exceed the payments that the doctors ultimately get from the insurance company. This indicates that the insurance companies are making profits.

 

The passage depends upon which one of the following assumptions? (more)

Studies have shown that children who watch a lot of television do not typically read above grade level. In the United States, more than three out of ten children watch television at least 35 hours per week. In other western countries, less than one child out of ten watches that much television. In contrast, these other children perform much better than American children on reading tests and more often read above grade level. A majority of these non American children read above their school grade level; a smaller percentage of American children read above grade level. In order to read as well as children in other western countries, American children will have to reduce the amount of time they spend watching television.

The passage depends upon which one of the following assumptions?

(A) American children are not as interested in reading well as children in other western countries.

(B) Other children are more structured in their studies than children in the United States.

(C) If a child wants to become a better reader, he or she will not watch as much television.

(D) If a child watches less television, his or her reading level will increase.

(E) The methods American teachers and parents use to teach reading are not significantly worse than the methods used by teachers and parents in other western countries.

The passage says, there is a study that shows children who watch a lot of TV do not typically read above grade level. This occurrence is common among children in the US as compared to children in other western countries. Non-American children perform better on reading tests compared to American children. The conclusion states that if American children want to read as well as children from other western countries, then American children will have to reduce the amount of time they spend watching TV.
Answer choice A is incorrect as there is no evidence to show that American children are not interested in reading. Answer choice B also has no evidence to support its claims. The passage does say that children who watch lesser TV are better at reading, but that does not necessarily mean that TV is the only thing that has an impact on reading, there could be other factors as well, like the interest of the child, the teacher, the pedagogy etc. Answer choice D is not an assumption, it is a finding that the passage clearly states. Answer choice E is correct as the passage seems to state that watching TV is the only factor that impacts reading. So the passage is assuming that the methods used by the teachers in America and other western countries are the same.