a. Harry's total wage for the week is $18.25 x 38 hours + ($18.25 x 1.5) x 9.5 hours + ($18.25 x 2) x 5.5 hours = $691.63.
b. For Monday, Jessica will earn $15.85 x 2.5 x 2.5 = $99.06. For Tuesday, Wednesday, and Thursday, she will earn $15.85 x 7 hours = $110.95 per day. For Friday, she will earn $0. For Saturday, she will earn $15.85 x 1.5 x 1.5 + $15.85 x 1.5 x 2 = $71.33. Jessica's total wage for the week is $99.06 + $110.95 x 3 + $71.33 = $503.24.
c. Ava will earn $7.21 x 2.5 hours + $7.21 x 1.5 hours + $7.21 x 5 hours + $7.21 x 1 hour + $7.21 x 8.5 hours + $7.21 x 2.5 hours = $143.08.
d. Under the new rate, Ava will earn $8.15 x 2.5 hours + $8.15 x 2.5 hours + $8.15 x 5 hours + $8.15 x 1 hour + $8.15 x 8.5 hours + $8.15 x 2.5 hours = $142.98. Ava will be slightly worse off under the new rate.