8 pumps can fill a tank in 20 mins. How much time will it take to fill the tank if only 5 of them are engaged?
The correct option is B 32 mins
8 pumps can fill a tank in 20 mins.
We know that if the number of pumps is less, it will take more time to fill the tank.
So, Number of pumps(x)∝1Time taken(y)
∴x1x2 = y2y1
x1 = 8 pumps
y1 = 20 mins
x2 = 5 pumps
and y2 = time taken to fill the tankby 5 pumps
⇒ y2 = x1 × y1x2
⇒ y2 = 8 × 205 = 32 mins
Hence, it will take 32 mins if only 5 pumps are engaged.