"If n is a positive integer, is n equal to 100?
(1) (sqrt)n > 9
(2) (sqrt)n < 11 "
According to the first statement n could be 100 or 121 or 144 or 169 and so on. So it's insufficient.
Statement 2 is also insufficient since n could 100 or 81 or 64 or 49 etc...
But if we combine them the result is n=100. So it should be C.
What is the O.A?
(sqrt)n
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Statement 1: √n > 9Malolo355 wrote:"If n is a positive integer, is n equal to 100?
(1) (sqrt)n > 9
(2) (sqrt)n < 11 "
According to the first statement n could be 100 or 121 or 144 or 169 and so on. So it's insufficient.
Statement 2 is also insufficient since n could 100 or 81 or 64 or 49 etc...
But if we combine them the result is n=100. So it should be C.
What is the O.A?
Squaring both sides, we get:
n > 81.
Since n can be ANY INTEGER greater than 81, INSUFFICIENT.
Statement 2: √n < 11
Squaring both sides, we get:
n < 121.
Since n can be ANY POSITIVE INTEGER less than 121, INSUFFICIENT.
Statements combined:
Since n can be ANY INTEGER between 81 and 121, INSUFFICIENT.
The correct answer is E.
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While the value of n itself must be an integer, nothing in the problem requires that √n be an integer.Malolo355 wrote:So in other words you claim that (sqrt)n could be a non-integer ?
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Hi Malolo355,
DS Questions are built to test a number of traits: organization, thoroughness, accuracy, attention-to-detail, etc.
Occasionally, you'll have to consider non-integers (fractions, decimals, etc.) when dealing with a DS question (and even some PS questions require a focus on non-integers). It doesn't happen very often, but if your goal is to score at a high level in the Quant, you have to be prepared to do a bit more work and think about more possibilities than just integers.
GMAT assassins aren't born, they're made,
Rich
DS Questions are built to test a number of traits: organization, thoroughness, accuracy, attention-to-detail, etc.
Occasionally, you'll have to consider non-integers (fractions, decimals, etc.) when dealing with a DS question (and even some PS questions require a focus on non-integers). It doesn't happen very often, but if your goal is to score at a high level in the Quant, you have to be prepared to do a bit more work and think about more possibilities than just integers.
GMAT assassins aren't born, they're made,
Rich