SOLUTION: The time required to fill a tank varies inversely as the square of the diameter of the pipe used. If it takes 20 hours to fill a given tank with a 2-in. pipe, find the diameter of

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Question 641062: The time required to fill a tank varies inversely as the square of the diameter of the pipe used. If it takes 20 hours to fill a given tank with a 2-in. pipe, find the diameter of the pipe needed to fill the same tank in 5 hours.
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
Inverse variation means that t=k/d^2 where k is the constant of proportionality
Sooo
20 hrs=k/2^2 or
k=80
Now
5hrs=80/d^2
5d^2=80
d^2=16
d=sqrt16=4 in
CK
5hrs=80/4^2
5hrs=80/16
5hrs=5hrs
Hope this helps---ptaylor