Question 314515
A pool can be filled with water in 10 hours Draining the pool requires 20 hours If the pool is empty and the drain is open how much time will be needed to fill the pool? 10,15, or 20 hours?
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Let x = time to fill pool
then
x(1/10 - 1/20) = 1
multiplying both sides by 20:
x(2 - 1) = 20
x(1) = 20
x = 20 hours