cost 15 to make the shoes, gave the boy 29 for change, and need 29 more to pay back the nieghborhood, so 15+29+29= 73. simple ,math problem. much easier than calculus~
5 X" R$ q& S. `/ b3 s% Y S( C5.39.217.77. U8 A h* z. I% m ?: A
[ 本帖最後由 carsonchan 於 2009-2-15 04:18 PM 編輯 ] |