Data Sufficiency

Hi NandishSS,

While this question looks complicated, it really comes down to 4 unknowns - what is the rate of each of the two types of machines and how many of each of those machines do we have. If we don't have all of those numbers, or a ratio defining how those numbers relate to one another, then then there's no way to answer the given prompt.

The question can be written as... Is (N)(rate of Machine A) > (K)(rate of Machine B)? This is a YES/NO question.

1) N > K

This Fact tell us that there are more Machine As than Machine Bs, but we don't know either of their rates.
Fact 1 is INSUFFICIENT.

2) The number of copies of the manuscript that n machines of type A can make in one hour is 20

This Fact tells us the value of (N)(rate of Machine A), but NOT the value of (K)(rate of Machine B).
Fact 2 is INSUFFICIENT.

Combined, we still don't know the rate of Machine B, so there's no way to answer the question.
Combined, INSUFFICIENT.

Final Answer: E

GMAT assassins aren't born, they're made,
Rich

NandishSS wrote:Is the number of copies of a certain manuscript that n machines of type A can make in one hour greater than the number of copies of the manuscript that k machines of type B can make in one hour?

(1) n>k

(2) The number of copies of the manuscript that n machines of type A can make in one hour is 20

OA:E

Source:GMATPrep EP1

This question can be solved through logical deduction approach.

There are two types of Xerox machines: type A and type B.

If type A machines are significantly efficient than type B, then even if there are fewer type A machine than type B, type A may beat type B. Not necessarily, though. It depends on how many type A and type B machines are there.

Statement 1 itself is obviously not sufficient since we do not know the rates of print per machine.

Similarly, statement 2 itself is obviously not sufficient since we do not know the rate of print per machine of type B and the count of machines of each type.

Even both the statements together are not sufficient since we still do not know the rate of the print of type B machine.

Answer: E

-Jay
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NandishSS wrote:Is the number of copies of a certain manuscript that n machines of type A can make in one hour greater than the number of copies of the manuscript that k machines of type B can make in one hour?

(1) n>k

(2) The number of copies of the manuscript that n machines of type A can make in one hour is 20

We need to determine whether the number of copies of a certain manuscript that n machines of type A can make in one hour is greater than the number of copies of the manuscript that k machines of type B can make in one hour.

If we let the rate of a type A machine = a and the rate of a type B machine = b, then the work done by n machines of type A in an hour is na and the work done by k machines of type B is kb. Thus, we need to determine:

na > kb ?

Statement One Alone:

n > k

Although we know that n is greater than k, without knowing the relationship between a and b, statement one is not sufficient to answer the question.

Statement Two Alone:

The number of copies of the manuscript that n machines of type A can make in one hour is 20.

Although we know that na = 20, we still do not know anything about k or b, thus statement two alone is not sufficient to answer the question.

Statements One and Two Together:

Using the information from statements one and two, we still do not have enough information to answer the question. We know that na = 20 and that n > k, however, we do not have any information about b.

Answer: E