If 4 pipes of same type can fill a tank in 2 hours 15 minutes, then how much time will 5 pipes of same type take to fill the tank ?

Correct option is B

4 pipes of same type can fill a tank = 2 hours 15 minutes
1 pipes of same type can fill a tank = 2 hours 15 minutes 4 = 9 hours
5 pipes of same type can fill a tank = 9/5 hours = 1 hour 48 minutes