One pump drains one-half of a pond in 2 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one-half hour. How long would it take the second pump to drain the pond if it had to do the job alone?  Choose the most appropriate option.
A) 1.3 hour  B) 1.2 hour  C) 3 hours  D) 5 hours  E) 6 hours
The tricky part here, I believed is one half hour = 1/2. Then everything would be easy.   We have the 1st pump working rate/hour = 1/2 : 2 = 1/4   Working rate of 2 pumps: 1/2 : 1/2 = 1.   Working rate of 2nd pump: 1 -1/4 = 3/4 --&gt; Time taken for the 2nd pump to finish: 1 : 3/4 = 4/3 = 1.3 hours.   1.3 hour
<result>A</result>
One pump drains one-half of a pond in 2 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one-half hour. How long would it take the second pump to drain the pond if it had to do the job alone?