A main pipe $150mm$ in diameter carrying $100$ltr$/$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 $3$m$/$s$.$

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

$...,90,100,110,120,...$ mm

Check if the main pipe velocity is in the acceptable range $($between $2$ and $3\frac{m}{s}).$