#### Answer

The water speed in each pipe is 3.5 m/s

#### Work Step by Step

We can find the volume flow rate of the water.
$flow~rate = \frac{V}{t}$
$flow~rate = \frac{(3.0\times 10^6~L)(\frac{1~m^3}{1000~L})}{60~s}$
$flow~rate = 50~m^3/s$
Note that the volume flow rate in each pipe is $25~m^3/s$.
The volume flow rate is the water speed times the cross-sectional area of the pipe. We can find the water speed in each pipe.
$flow~rate = v~A = 25~m^3/s$
$v = \frac{25~m^3/s}{\pi~r^2}$
$v = \frac{25~m^3/s}{(\pi)(1.5~m)^2}$
$v = 3.5~m/s$
The water speed in each pipe is 3.5 m/s.