One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one and half hour. How long would it take the second pump to drain the pond if it had to do the job alone?
Here, 1 hour = 60 minutes.
∴ 24 hour = 24 x 60 = 1440 minutes.
The Dolphin comes up air in 1440 minutes =14402 =720 times
& The Whale comes up air in 1440 minutes =14405 =288 times.
∴Required percentage = (720-288288×100) = (432288 ×100)% = 150%
On average, the bottle-nosed dolphin comes up for air once every two minutes; the beluga whale, close relative, comes up for air on average once every five minutes. The number of times a bottle-dolphin would come up for air in a 24 hour period is approximately what percent greater than number of times a beluga whale would come up for air in that same period?
The first pump can drain in 3 hours 12 of the pond
∴The first pump can drain in 1 hours=12×3=16 of the pond
Both pumps can drain in 112or32 hours=1-12=12 of the pond.
∴Both pumps can drain in 1 hours =12×13=13 of the pond.
∴Working alone the second pump can drain in 1 hour =13-16=2-16=16 part of the pond
∴The second pumps can empty 16 of the pond in 1 hour
∴The second pump can empty 1 or full pond n = 6 × 11 = 6 hours.