Hi ardz24,
We're told that a fruit salad mixture consists of apples, peaches, and grapes. There are 3 times as many pounds of apples as grapes and 5/2 times as many pounds of peaches as grapes. We're told that a mixture has an AVERAGE of 13 pounds of EACH of the 3 fruits. We're asked how many MORE pounds of apples than grapes the mixture has.
Since the total amount of fruit in the mixture is relatively small, we can do a bit of 'brute force' arithmetic to answer this question. To start, with an AVERAGE of 13 pounds of each type of fruit, there would be 3(13) = 39 total pounds of fruit in the mixture. Given the ratios of fruit involved, we know...
IF.....
we have 1 pound of grapes, then we have 3 pounds of apples and 2.5 pounds of peaches.... total weight = 1+3+2.5 = 6.5 pounds
with 2 pounds of grapes, we have 6 pounds of apples and 5 pounds of peaches... total weight = 2+6+5 = 13 pounds
Etc.
Notice that if we TRIPLE the second option, then we'll have 39 total pounds of fruit...
6 pounds of grapes, 18 pounds of apples and 15 pounds of peaches... total weight = 6+18+15 = 39 pounds.
The 39-pound total is an exact match for what we were told, so we know there are 18 pounds of apples and 6 pounds of grapes. Thus, there are 18-6 = 12 MORE pounds of apples than grapes in the mixture.
Final Answer: B
GMAT assassins aren't born, they're made,
Rich
