Question

Three tops A, B and C can fill a tanks in 8, 10
and 12 hours respectively. The tap A is open all the
time continuously. But tops B and C are open
o for.
one hour each alternately. How long will it take
the tank
to be full
?​

Answer 1

Answer: 7hrs

Given : A,B,C taps fill the tank in 12, 15,20.

To solve this fist we to find out total work that would be LCM of 12,15,20 = 60 (capacity of tank)

Now find out the individual works of A,B,C

Individual work of A=5units

Similarly B=4units , C = 3units/hr

A is open all the time and B and C are open alternatively

A+B = 5+4 =9units/hr

A+C=5+3=8units/hr

Total of 17units in 2hrs

Total capacity = 60/17 = 3.5 ×2hrs

Tank will be filled in 3.5×2hrs = 7hrs