Question 965113
one pump can drain a pool in 3 minutes. when a second pump is also used, the poo; only takes 2 minutes to drain. How long would it take the second pump to drain the pool if it were the only pump in use?
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1st pump can drain the pool in 3 min by itself
1/3=its drain rate
2nd pump can drain the pool in x min by itself
1/x=its drain rate
1st and 2nd pumps working together can drain the pool in 2 min
their drain rate=1/2
..
sum of indv. rates=rate working together
1/3+1/x=1/2
1/x=1/2-1/3=3/6-2/6=1/6
x=6
How long would it take the second pump to drain the pool if it were the only pump in use? 6 min