根本不用韦恩图，搞清楚分母，60% of the passengers with 往返票, 指有往返票的人数的60%

20 percent of a ship’s passengers，20%*总人数。 60 percent of the passengers with round-trip tickets ，60%*有双票的人 。 原来这样啊。我还以为 60 percent of the passengers with round-trip tickets 是60%的乘客有round trip 票呢。

搞清占比的分母

这道题确实很绕，需要读懂题目

passenger total is P, and Round Trip people totalled R. then: (1-60%)R=20%P, so R/P= 50%. I checked all my wrong record, 80% above was wrong because misunderstanding the words :(

上一条有地方打错了
假设共有乘客y人，其中拥有往返票的有x人
20 percent of a ship's passengers held round-trip tickets and also took their cars aboard the ship.，说明20%y是有往返票且带车上船的
If 60 percent of the passengers with round-trip tickets did not take their cars aboard the ship, 所以40%*x是有往返票且带车上船的
所以20%y=40%x
x=1/2*y=50%y

假设共有乘客y人，其中拥有往返票的有x人
20 percent of a ship's passengers held round-trip tickets and also took their cars aboard the ship.，说明20%y=x
If 60 percent of the passengers with round-trip tickets did not take their cars aboard the ship, 所以40%*x是有往返票且带车上船的
所以20%y=40%x
x=1/2*y=50%y

读懂题意