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## Homework Statement

An old two pipe system runs through a hill, with distances D_a=D_b=30m and the total Distance is D=110m. On each side of the hill, the pipe radius is .0200m. However, the radius of the pipe inside the hill is no longer known. To determine it, hydraulic engineers first establish that the water flows through the left and right sections at 2.50m/s. Then they release a dye in the water at point A and find that it takes 88.8s to reach point B. What is the average radius of the pipe within the hill (sorry i don't have a diagram)?

## Homework Equations

AoVo=AV

v=d/t

## The Attempt at a Solution

I cut this problem in half to try and make it work. I used AoVo=AV where Ao is the little pipe, and A is the the middle pipe.

AoVo=AV>>>>(pi_r^2)(2.50m/s)=(pi_r^2)(V)

solve for r^2 on right

(pi_r^2)(2.50m/s)=(pi_r^2)(d/t)>>>>sq. root(.02^2)(2.50m/s)(44.4s) / 55m= .03m

i know i am going wrong in many places. Any suggestions?