On a certain road, 10% of the motorists exceed the posted speed limit and receive speeding tickets, but 40% of the motorists who exceed the posted speed limit do not receive speeding tickets. What percent of the motorists on that road exceed the posted speed limit?	Choices
A) 10.5 % B) 12.5 % C) 16.7 % D) 25 % E) 30 %

Rationale: "suppose there are x motorists . 10 % of them exceeded the speed limit and received the ticket , i . e . x / 10 . again , suppose total no . of motorists who exceeded the speed limit are y . 40 % of y exceeded the speed limit but did n ' t received the ticket , i . e . 2 y / 5 . it means 3 y / 5 received the ticket . hence , 3 y / 5 = x / 10 or y / x = 1 / 6 or y / x * 100 = 1 / 6 * 100 = 16.7 % c"
Answer: C