Question

Two pipes a and b can fill a cistern in 37 1 2 minutes and 45 minutes respectively. both pipes are opened. the cistern will be filled in just half an hour, if pipe b is turned off after

a. 5 min b. 9 min

c. 10 min d. 15 min

Answer 1

ans is d. 15 min as both the pipes take half an hour