[問題] GWD21-23

[little8]

Q23:
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?

A. 33 %
B. 40%
C. 50%
D. 60%
E. 66 %

Answer:C

百思不得其解,懇請高人指點..

[medi66]

設全部的乘客為X 有round-trip tickets的乘客為T
由"20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship"
可知 有tickets又帶車上船的人是20%X
由"If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship"
同樣可知 有tickets又帶車上船的人是(1-60%)T= 40%T
兩條件 劃上等號以後 就可以求出答案

[chris8888]

如圖