If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1)One of the machines produces copies at the constant rate of 250 copies per minute.
(2)One of the machines produces copies at twice the constant rate of the other machine.
答案E可是我覺得是C 題目不就是要問兩台一起印五分鐘可以印多少嗎 那(1) (2)連在一起不就可以有答案了 為什麼是E呢?