Question

If $12$ pumps can empty a reservoir in $20$ hours then the time required by $45$ such pumps to empty the same reservoir is ____ hours.

Answer 1

Step $1:$ Calculate the time taken by $1$ pump to empty the reservoir.

Since the time taken by $12$ pumps to empty the reservoir is $20$ hours.

Therefore, The time taken by $1$ pump to empty the reservoir is $20\times 12=240$ hours.

Step $2:$ Calculate the required time.

Since the time taken by $1$ pumps to empty the reservoir is $240$ hours.

Therefore, the time taken by $45$ pumps to empty the reservoir is $\frac{240}{45}=5.33$ hours.

Hence, the time required by $45$ pumps to empty the reservoir is $5.33$ hours.