A tank contains 500 gallons of saltwater solution containing

A tank contains 500 gallons of salt-water solution containing 0.05 lb of salt per gallon of water. Pure water is pumped into the tank and a drain is opened at the bottom of the tank, adjusted so that the volume of solution in the tank is constant. At what rate (gal/min) should the water be poured into the tank to lower the salt concentration to 0.01 lb/gal of water in under one hour?

Solution

Given:500 gallons of solt water contain 0.05 lb of salt per gallon.

        after 60 min it became 0.01 lb of salt per gallon.

         Now The rate of (gal/min) should the water be poured into the tank as 0.01lb of salt in water is:

                                    =500/60

                                     =8.33 gal/min.