One pump drains one-half of a pond in 6 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 correct option:
A) 1 hour  B) 1.09 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 :6 = 1/12   Working rate of 2 pumps: 1/2 : 1/2 = 1.   Working rate of 2nd pump: 1 -1/12= 11/12 --&gt; Time taken for the 2nd pump to finish: 1 : 11/12 = 12/11 = 1.09 hours.   1.09 hour
<result>B</result>
One pump drains one-half of a pond in 6 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?