swerve wrote:One pipe can fill a pool 1.25 times faster than second pipe. When two pipes are opened, they fill the pool in five hours. How long would it take to fill the pool if only the slower pipe is used?
A. 11.25
B. 11.52
C. 1.25
D. 9
E. 7.2
Let rate for the slower pipe = 4 liters per hour.
Since the faster pipe is 1.25 times faster, the rate for the faster pipe = (1.25)(4) = 5 liters per hour.
Combined rate for the two pipes = 4+5 = 9 liters per hour.
Since the two pipes working together at a rate of 9 liters per hour can fill the pool in 5 hours, the pool = rt = 9*5 = 45 liters.
Since the slower pipe's rate = 4 liters per hour, the time for the slower pipe to fill the 45-liter pool = w/r = 45/4 = 11.25 hours.
The correct answer is
A.
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