Candice leaves on a trip driving at 35 miles per hour. Three hours later, her sister Liz starts from the same location driving at 50 miles per hour. How long after Liz leaves home will she catch up to Candice? 7 hours

9 hours

10 hours

3 hours

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).