The task is to generate the correct answer for a given math problem.

[EX Q]: Problem: in township k , 1 / 5 of the housing units are equipped with cable television . if 1 / 10 of the housing units , including 1 / 3 of those that are equipped with cable television , are equipped with videocassette recorders , what fraction of the housing units have neither cable television nor videocassette recorders ?
[EX A]: 23 / 30

[EX Q]: Problem: how many digits are required to number a book containing 240 pages ?
[EX A]: 612

[EX Q]: Problem: 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 ?
[EX A]:
20 %