The number of stamps that P and Q had were in the ratio of 5:3 respectively. After P gave Q 10 stamps, the ratio of the number of P's stamps to the number of Q's stamps was 9:7. As a result of the gift, P had how many more stamps than Q?  Pick one: A) 20 B) 30 C) 40 D) 60 E) 90
P started with 5k stamps and Q started with 3k stamps.   (5k-10)/(3k+10) = 9/7   35k - 27k = 160   k = 20   P has 5(20) - 10 = 90 stamps and Q has 3(20)+10 = 70 stamps.   The answer is 20.
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The number of stamps that P and Q had were in the ratio of 5:3 respectively. After P gave Q 10 stamps, the ratio of the number of P's stamps to the number of Q's stamps was 9:7. As a result of the gift, P had how many more stamps than Q?