Question

three pipes a, b and c can fill in 5 hours, 10 hours, 15 hours respectively in how many hours all three pipes will fill the tank together

Answer 1

A= 5 h
B= 10h
C= 15 h
since the most common divisible no. is 30
let total work or capacity of tank = 30 liters
now calculating per hour work
A= 6 unit per hour
B= 3unit per hour
C= 2 unit per hour
together A+B + C = 11 unit per hour

time taken by 3 pipe= total work or tank capacity/ together work per hour
= 30/11
=2.72 hour
or 2+ 60min or 1 hour +12 min
= 3 hour 12 min