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
