If Taryn and Alistair want to earn an additional $735 each, how many hours will each spend mowing lawns

If Taryn mowed 9 lawns in 7.5 hours and earned $112.50, then her hourly rate is:

$112.50 / 7.5 hrs = $15 per hour

If Alistair mowed 7 lawns in 5 hrs and earned $122.50, then her hourly rate is:

$122.50 / 5 hrs = $24.50 per hour

To earn an additional $735 each, they should work the following hours.

Taryn: $735 / $15 = 49 hours

Alistain: $735 / $24.50 = 30 hours