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 1/3%
B. 40%
C. 50%
D. 60%
E. 66 2/3%

Thank you for your help!

The question statement gives us the following:


Let's denote the number of people on the round trip by x and the number of people who travel one-way by y.
On one side, the number of people on the round trip with a car is 40% of the people on the round trip, which is 0.4x.
On the other side they make 20% of all the passengers, which is 0.2(x + y).
0.4x = 0.2x + 0.2y
x = y

That means that the round trip passengers make x / (x + y) = x/(2x) = 1/2 = 50%.
The correct answer is C.