9. Sales for a speaker system have been growing at the rate: f ' (t) = 2000(3 Ze't) systems/yr where t is the number of years they have been on the market. How many systems Where sold in the 15' 5 years? 10. The sales of Universal Systems in the 15t t years are given by:S(t) = V0.2t + 4- where S(t) is in millions. Find the average yearly sales in the 1St 10 years of operations