对于一道数学题的理解产生的疑惑

Etoile-

A marketing 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 of the 200 households surveyed used both brands of soap?


想问问大家and for every household that used both brands of soap, 3 used only Brand B soap.这句话是怎么理解的

TCSH

只用B的是即用A又用B的三倍？那么答案是15，如果对的话那应该是这个意思吧

Jez

哈哈我做OG第一个问题也是这个理解
它是这个意思——only use B：use both A and B =3:1
直译过来会比较怪，对于每个同时使用AB的家庭，有三个家庭只用B。

恭喜你开始了gmat旅程！