Dvaishnav
My answer was D.
I am not able to understand the reasoning behind statement 1 as insuffucient. The question is asking "is it possible to get integer values of n/m" It is NOT asking if n/m is an integer. As most of the posts here have pointed out that statement 1 also provides at least one possible solution where n/m is an integer (for example: n = 20, m = 10) So, even with statement 1 alone, we can answer that IT IS POSSIBLE.
Can someone please help? Thanks.
Yeah, good question. A couple of points to make here:
1. No DS question will ever ask whether something is possible, so if you interpret a question that way you're certainly mistaken. To illustrate, consider the following example:
Is it possible that x is positive?
(1) x<0
(2) x<3
Each statement is sufficient on its own: (1) gives a definite NO and (2) gives a "definite" YES. [side note: statements can't lead to different definite answers since that would mean one of them is false, which is not a thing on the GMAT]
Another example:
Is it possible that x is positive?
(1) x>0
(2) x>-3
Again each statement is sufficient on its own. Can you create a statement that
wouldn't be sufficient to answer the question "Is it possible that x is positive?" - such a statement doesn't exist.
Side note: this isn't just for YES/NO questions - same goes for value questions (think about it).
2. Why is it wrong to rephrase the original question to "is it possible that n/m is an integer?"
Under what circumstances would it be possible to assign each of the N students to one of the M classrooms so that each classroom has the same number of students assigned to it?
This would ONLY be possible if n/m is an integer. So, if n/m is an integer the answer is YES (it's possible), and if n/m isn't an integer then the answer is NO (it's not possible).
Therefore, the correct rephrase is: is n/m an integer?
By the way, the second section of my book is dedicated exclusively to DS strategy, and you can read it for free at quantreasoning.com