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~
( |: K2 Q. `; \! O3 l a/ U1 utvb now,tvbnow,bttvb
1 _; v, W% y6 X$ |[ 本帖最後由 carsonchan 於 2009-2-15 04:18 PM 編輯 ] |