Flow rate

geowills

A large tank at first has 50 gallons of a solution that is holding 10 lbs. of a chemical. Water is going through at a constant rate, and the mixture is going out at a constant rate. What will be the flow rate if 2 lbs. remains after 20 mins?

I assume it's a differential eqns. problem.
I think I should define x(t) as amount of chemical, so dx/dt = - x(t)/50 but I'm not really sure. Can somebody walk me through this?

Hakins90

Well the water and chemical is decreasing at a constant rate so i doubt you should use differential equations.

Here is what i think -

8lb of chemical in 20 mins = 0.4lb/min
50 gallons for 10 lb of chemical = 5gal/lb

gallons/min = 0.4 * 5 = 2 gal/min