Que es mezcla de mercadotecnia

Alarge tank is filled to capacity with 500 gallons of pure water. brine containing 2 pounds of salt per gallon is pumped into the tank at a rate of 5 gal/min. the well-mixed solution is pumped out at the same rate. find the number a(t) of pounds of salt in the tank at time t.

Qwest airlines has implemented a program to recycle all plastic drink cups used on their aircraft. their goal is to generate $7 million by the end of the recycle program's five-year life. each recycled cup can be sold for $0.005 (1/2 cent). a. how many cups must be recycled annually to meet this goal? assume uniform annual plastic cup usage and a 0% interest rate. b. repeat part (a) when the annual interest rate is 12%. c. why is the answer to part (b) less than the answer to part (a)?

River corp's total assets at the end of last year were $415,000 and its net income was $32,750. what was its return on total assets? a. 7.89%b. 8.29%c. 8.70%d. 9.14%e. 9.59%