数学问题~~~~

徐小涵

A marketing firm determined that of 200 households surveyed, 80used neither Brand A nor Brand B soap,60 used only Brand A soap. and for every household that used both brands of soap,3 used only Brand B soap. How many of the 200 households surveyed used both brands of soap?

(A)15
(B)20
(C)30
(D)40
(E)45

求指导翻译题目啊 看不懂啊 本人小白 谢谢各位

melod_gogogo

你是JN的小涵嘛！！！！

徐小涵

melod_gogogo 发表于 2013-12-16 15:41
你是JN的小涵嘛！！！！

JN是啥？！