Question

Pipe a can fill a tank in 5 hours, pipe b in 10 hours and pipe c in 30 hours. if all the pipes are open, in how many hours will the tank be filled ?

Answer 1

Pipe a can fill a tank in 5 hours
Pipe b can fill a tank in 10 hours
Pipe c can fill a tank in 30 hours
the a pipe can fill in one hour the tank is 1/5
the b pipe can fill in one hour the tank is 1/10
the c pipe can fill in one hour the tank is 1/30
all the pipes can fill in one hour the tank
=1/5+1/10+1/30
=6+3+1/30
=10/30
=1/3
so, all together can fill the tank in 3 hours