# Mixing problem

there's an example problem in my textbook, but i'm stuck on how to make the first move~
"a tank contains 1000gal of water in which 200lb of salt are dissolved. Fifty gallonw of brine, each containing (1+cost)lb of dissolbed salt, run into the tank per minute. The mixture, kept uniform by stirring, runs out the same rate. Find the amount of salt y(t) in the tank at any time t."

Tide
Homework Helper
HINT: $$\frac{dA}{dt} = r_{in} - r_{out}$$

where A is the amount of salt in the tank and r is the rate of salt flow in or out of the tank.

rate in = 50 lbs/min * (1+cost)lb / gal

rate in = y(t) / 1000 gal

dv /dt = rin - rout

find the intergating factor and ....

Why's rate out = y(t)/1000 gal?

HallsofIvy