菜鸟弱弱的问个OG数学题

heartily

刚接触GMAT, 看了OG上一道数学题看不懂, 请大虾们指导一下:

A maketing firm determined that, of 200 households surveyed, 80 used 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......

划线的部分如何解释为 "用B的是用两种人数的3倍?"

我根本读不出来......

fighting127

for every household that used both brands of soap, 3 household used only Brand B soap.

这样清楚些吧?所以用B的人数是两种都用的人数的3倍

heartily

基本上明白了, 多谢 fighting127