A main pipe $150mm$ in diameter carrying $100li\frac{t}{s}$ water. The pipe will be equally divided into three pipes with the same diameter. Find a proper size for the three pipes to keep the velocity in the range of $2$ to $3\frac{m}{s}.$

You should select the diameter of the pipes as multiples of $10$:

$...,90,100,110,120,$dotsmm

Check if the main pipe velocity is in the acceptable range $($between $2$ and $3\frac{m}{s}).$ Do not forget to check the velocity of main pipe.