Penelope works as a lifeguard at the neighborhood pool. The chart shows

how much money she earns based on the number of hours she works.

Number

of hours

worked

Money

earned

3.5

$26.25

5

$37.50

7

$52.50

Mark has a job stocking groceries that pays $W per hour.

a. How much would Penelope make for working 8 hours?

b. How much would Mark make for working 8 hours?