You want to separate all the coal particles having a diameter of 100 m or larger from

You want to separate all the coal particles having a diameter of 100 μm or larger from a slurry. To do this, the slurry is pumped into the bottom of a large tank. It flows upward and overflows over the top of the tank, where it is collected in a trough. If the coal has SG = 1.4 and the total flow rate is 250 gpm, how big should the tank be?