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 choice from the following choices
A) 1 hour  B) 1.1 hour  C) 3 hours  D) 5 hours  E) 6 hours
First pump drains 1/2 of the tank in 6 hours   so 12 hours it will take to drain the full tank.   Let, 2nd pump drains the full tank in a hours   so both together can drain (1/12+1/a) part in 1 hour   son in 1/2 hour they drain 1/2*(1/12+1/a) part of the tank   given that in 1/2 hour they drain 1/2 of the tank   hence we can say   1/2*(1/12+1/a) = 1/2   solving u get a = 12/11=1.1   Hence answer is 1.1 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?