Arithmetic DS Question

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Source: — Data Sufficiency |

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by Brent@GMATPrepNow » Thu Jun 27, 2013 6:40 am
snigdha1605 wrote:Is T/S > F/G ?

a) T < S
b) F > G
Target question: Is T/S > F/G ?

To begin, since each statement mentions only 2 of the 4 variables, we can automatically jump to . . .

Statements 1 and 2 combined:
At this point, all we know is the relative values of the numbers in each fraction. However, we know nothing about whether or not any of these 4 values are positive or negative. For example, it could be the case that T = 1 and S = 2, or it could be the case that T = -1 and S = 2, etc.

So, the fractions T/S and F/G can be either positive or negative, so there's no way to determine whether one is greater than the other.

Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E


Aside: here's proof that the combined statements are NOT SUFFICIENT.
case a: T = 1, S = 2, F = 2, G = -1, in which case T/S > F/G
case b: T = 1, S = 2, F = 2, G = 1, in which case T/S < F/G

Cheers,
Brent
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by snigdha1605 » Thu Jun 27, 2013 7:09 am
Thanks Brent!