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~
, W- I8 {& F( l' `) Gtvb now,tvbnow,bttvb0 v6 `) P" I9 q$ z& j' h7 P4 W
[ 本帖最後由 carsonchan 於 2009-2-15 04:18 PM 編輯 ] |