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~
3 B8 [% y8 m# |7 d, m公仔箱論壇5 b( C+ w& ^5 Q% h* `: @( O% T
[ 本帖最後由 carsonchan 於 2009-2-15 04:18 PM 編輯 ] |