11. In seven years, Seta's son Stu is leaving home for college. Seta hopes to save $8000 to
help pay for his first year, She has $5000 now and has found a bank that pays 7.75%
interest, compounded daily. At this rate, will she have the money she needs for Stu's first
year of college? If not, how much more does she need?

the answer is 31.27mph

the revenue of the fitness center, y, is the product of two factors: the number of members and the fee paid by each member. there are 320 members now, but number of members goes down by 10 for each $5 increase in fees, so if x is the number of $5 price increases then members is equal to (320 - 10x). since the fee is currently $45, and the fee increases by $5 for every price bump x, the fee is given by (45 + 5x). so, revenue y is given by y = (320 - 10x)(45 + 5x).