SOLUTION: I need help setting this up- I have no ideas on this one. "An old water pipe is to be replaced by a new one so that twice as much water can flow through the pipe. What is the rati

Algebra ->  Radicals -> SOLUTION: I need help setting this up- I have no ideas on this one. "An old water pipe is to be replaced by a new one so that twice as much water can flow through the pipe. What is the rati      Log On


   

Question 876455: I need help setting this up- I have no ideas on this one.
"An old water pipe is to be replaced by a new one so that twice as much water can flow through the pipe. What is the ratio of the radius of the new pipe to that of the old pipe?"
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
"An old water pipe is to be replaced by a new one so that twice as much water can flow through the pipe. What is the ratio of the radius of the new pipe to that of the old pipe?"
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Assuming 2x the flow rate --> 2x the area:
Area+=+pi%2Ar%5E2
2%2AArea+=+pi%2A%28k%2Ar%29%5E2+=+pi%2Ak%5E2%2Ar%5E2 k = some number
k%5E2+=+2
k+=+sqrt%282%29
r of new pipe = sqrt%282%29*r of the old pipe