Five drainage pipes, each draining water from a pool at the same constant rate, together can drain a certain pool in 12 days. How many additional pipes, each draining water at the same constant rate, will be needed to drain the pool in 6 days? Select the correct option:
A) 5
B) 9
C) 10
D) 12
E) 15
This is an inverse proportional problem......   5 pipes in 12 days; So for 6 days, it will be = 12 x 5 / 6 = 10   So, 10-5 = 5   5nswer 5
<result>A</result>
Five drainage pipes, each draining water from a pool at the same constant rate, together can drain a certain pool in 12 days. How many additional pipes, each draining water at the same constant rate, will be needed to drain the pool in 6 days?