In a certain parking lot, 4% of the cars are towed for parking illegally. However 80% of the cars which are parked illegally are not towed. What percentage of cars in the parking lot are parked illegally? Choose one.
A) 20% B) 25% C) 30% D) 35% E) 40%
Let x be the number of cars and let y be the number of cars parked illegally.   4%*x = 20%*y   y/x = 1/5 = 20%   The answer is 20%.
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In a certain parking lot, 4% of the cars are towed for parking illegally. However 80% of the cars which are parked illegally are not towed. What percentage of cars in the parking lot are parked illegally?