PP-T２-５

[max999]

Working alone at its own constant rate, a machine seals k cartons in 8 hours, and working alone at its own constant rate, a second machine seals k cartons in 4 hours. If the two machines, each working at its own constant rate and for the same period of time, together sealed a certain number of cartons, what percent of the cartons were sealed by the machine working at the faster rate?

(A) 25%
(B)
(C) 50%
(D)
(E) 75%

ans: Ｄ

[nemolee]

http://www.formosamba.com/phpBB3/viewtopi ... stant+rate

http://www.formosamba.com/phpBB3/viewtopi ... stant+rate

為什麼你的問題要連開２個板呢？　而且都是一樣的
題目不完整也可以從搜尋裡找得到押.... 版上面有很多別人問過一模一樣的題目... 沒有再po上來 !!!!!