Direction: Given below are three quantities named A, B and C. Based on the given information, you have to determine the relation between these three quantities. You should use the given data and your knowledge of mathematics to choose among the possible answer.

Three taps 1, 2, 3 are connected to a cistern. Tap 1 and 2 are inlet taps which can fill the cistern alone in 10 hours and 15 hours respectively. Tap 3 is an outlet pipe which alone can empty the tank in 18 hours.

Quantity A: If tap 1 is kept open all the time and tap 2 and 3 is opened alternatively for an hour then find in how many hours the tank will be filled?

Quantity B: All the pipes are opened together, then find the time taken to fill the tank?

Quantity C: If tap 3 is kept open all the time and tap 1 and 2 is opened alternatively for an hour then find in how many hours the tank will be filled?