Hi hazelnun01,
This question is based on 'rounding' rules. We're told that 1500 is the multiple of 100 that is closest to X and that 2500 is the multiple of 100 that is closest to Y. This means that X and Y have the following ranges...
1450 <= X < 1550
2450 <= Y < 2550
We're asked for the multiple of 100 that is closets to (X+Y). We can TEST VALUES to answer this question.
(1) X < 1,500
IF....
X = 1499, Y = 2450, then (X+Y) = 3949 and the answer to the question is 3900
X = 1499, Y = 2499, then (X+Y) = 3998 and the answer to the question is 4000
Fact 1 is INSUFFICIENT
(2) Y < 2,500
The same two TESTs that I used in Fact 1 also 'fit' Fact 2...
IF....
X = 1499, Y = 2450, then (X+Y) = 3949 and the answer to the question is 3900
X = 1499, Y = 2499, then (X+Y) = 3998 and the answer to the question is 4000
Fact 2 is INSUFFICIENT
Combined, we already have two TESTs that fit both Facts and produce different answers.
Combined, INSUFFICIENT.
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
