# Calculus

posted by
**Thomas**
.

A large tank is filled with 200 gallons of pure water. Brine containing 1 pound of

salt per gallon is pumped into the tank at the rate of 5 gallon per minute. The

well-mixed solution is pumped out at the same rate.

(a) Find the number A(t) of pounds of salt in the tank at any time t.

Please help! I am getting the wrong solution.