On a certain transatlantic crossing, 40 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship. If 50 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?  Choose the correct choice.
A) 40%  B) 50%  C) 60%  D) 80%  E) 90%
Let T be the total number of passengers.   Let x be the number of people with round trip tickets.   0.4T had round trip tickets and took their cars.   0.5x had round trip tickets and took their cars.   0.5x = 0.4T   x = 0.8T   The answer is 80%.
<result>D</result>
On a certain transatlantic crossing, 40 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship. If 50 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?