Two full 100 gal. mixing barrels are connected in following way. Container A has 3 gallons of brine coming in for each minute which contains 2 lbs. of salt per gal.. the solution in tank A is forced in tank B which feeds 1 gal. per minute back into tank A and 3 gal per minute to an exit pipe. Tank A initially has 40 lbs. of salt and tank B 30 lbs. Set up the initial value system for this situation.