Hi alanforde800Maximus,
We're told that Jim bought a quantity of similar donuts, for which he was charged a total of $15. As the donuts were being boxed, Jim noticed that a few of them were slightly ragged-looking so he complained to the clerk, who apologized and then gave Jim 3 EXTRA donuts for free to make up for the damaged goods. As Jim left the shop, he realized that due to the addition of the 3 free donuts, the effective price of the donuts was reduced by $2 per dozen. We're asked for the total number of donuts Jim received in the end. This question can be solved Algebraically or by TESTing THE ANSWERS.
We know that a certain number of donuts were bought for $15, which would give us a certain price/dozen. After getting another 3 donuts for free, the price/dozen for all the donuts drops $2 EXACTLY. The fact that the difference is an integer is interesting - this makes me think that the original number of donuts (X) and the larger number of donuts (X+3) both "relate" nicely to the number 12. $2 is also relatively small compared to $15, so the correct answer will probably be one of the smaller answers.
Let's TEST Answer A first...
Answer A: 18 total donuts
Final number of donuts = 18 (this is a nice number - it's exactly 1.5 dozen donuts)
Initial number of donuts = 15 (this is also relatively nice - it's exactly 1.25 dozen donuts)
18 donuts for $15 = 1.5 dozen for $15 = $10 per dozen
15 donuts for $15 = 1 donut for $1 = $12 per dozen
The difference here is $2, which is a MATCH for what we were told.
Final Answer: A
GMAT assassins aren't born, they're made,
Rich