- #1
shanshan
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Homework Statement
A conical reservoir is 50m deep and 200m across the top. Water is being pumped in at a rate of 7000m^3/min, and at the same time, water is being drained out at a rate of 9000 m^3/min. What is the change in diameter when the height of the water in the reservoir is 20m?
Homework Equations
v=(1/3)pi(r^2)(h)
The Attempt at a Solution
h=(.5r)
v=(1/3)(pi)(r^2)(.5r)
=(1/6)(pi)(r^3)
v'=(.5)(pi)(r^2)(r')
7000=.5pi(40^2)(r')
= 2.785
-9000= .5pi(40^2)(r')
=-3.581
2.785-3.581 = -0.796 m/min
my answer, however, is supposed to be -1.6m/min