Question

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

Answer 1

If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is 5h 20 min hours.

Explanation:

∵ 12 pumps can empty a reservoir in 20 h.

∴ 1 pump can empty in 20 × 12 i.e. 240 h.

Then, 45 pumps can empty the same reservoir in

`240/45 h = (240 xx 60)/45 min`  ...[∵ 1 h = 60 min]

= `14400/45`

= 320 min

= 5 × 60 + 20

= 5h 20 min