关于GMAT数学题的问题on a certain transatlantic crossing,20 percent of a ship's passengers held round-trip tickets and also took their cars abroad the ship.if 60 percent of the passengers with round-trip tickets did not take their cars abroad

关于GMAT数学题的问题on a certain transatlantic crossing,20 percent of a ship's passengers held round-trip tickets and also took their cars abroad the ship.if 60 percent of the passengers with round-trip tickets did not take their cars abroad
关于GMAT数学题的问题
on a certain transatlantic crossing,20 percent of a ship's passengers held round-trip tickets and also took their cars abroad the ship.if 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship,what percent of the ship's passengers held round-trip tickets?
在一次横渡大西洋中,20%的乘客有round-trip然后带着他们的车上船.如果60%的乘客有round-trip没有带车上船,问：有多少百分比的乘客有round-trip?
a.33.3333333% b.40% c.50% d.60% e.66.6666666666666%
机经上的一道题~~~做不来
Freiheit1218提到：持有往返票（round-trip）并带着车的占总乘客数的20%；所有持有往返票的乘客中，没带车的占60%。
那么也就是说：持有往返票并带着车的乘客占总乘客数的（1-60%）
也就是说题目其实在问实际乘船人数和理论乘船人数的百分比是伐！？

关于GMAT数学题的问题on a certain transatlantic crossing,20 percent of a ship's passengers held round-trip tickets and also took their cars abroad the ship.if 60 percent of the passengers with round-trip tickets did not take their cars abroad
c
1.理解题意
条件：
a船上所有乘客中的百分之二十持有双程票并带自己的车上船
b持有双程票的所有乘客中的百分之六十没有带自己的车上船
提问：
船上所有乘客中的百分之几的持有双程票?
2.分析
由条件b,推得所有持有双程票的乘客中有百分之四十带自己的车上船,这就是所有的持有双程票并且带自己的车上船的乘客,即满足条件a,占船上所有乘客的百分之二十.
持有双程票并带车的人+持有双程票并没带车的人=所求答案
故：得50%,选c.

翻译的也不大对头，应该是：持有往返票（round-trip）并带着车的占总乘客数的20%；所有持有往返票的乘客中，没带车的占60%。
那么也就是说：持有往返票并带着车的乘客占总乘客数的（1-60%）
所以：
20%除以（1-60%）=50%
选C

20%/（1-60%）=50%

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