saumzi wrote:
i know its terribly easy but still i m stuck somewhere...
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-half hour.How long would it take the second pump to drain the pond if it had to do the job alone???
A.1 hour
B.1.2 hour
C.3 hours
D.5 hours
E.6 hours
Can you please check the question? I am getting the answer which is not in option.
Pump 1 drains half of the pond in 3 hrs ==>it will take 6hrs for Pump 1 to drain the entire pond.
Number of hrs taken by pump 2 = Y
If both pumps working together will empty the pond in 1.5hrs==>3/2
==>1/6 + 1/Y = 2/3
==>1/Y = 2/3-1/6 ==>(4-1)/6 =1/2
Y =2
Number of hrs taken by Pump 2 to drain the entire pond = 2hrs
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