9. $112.50 / 9 lawns = $12.50 per lawn
10. $122.50 / 7 lawns = $17.50 per lawn
11. $112.50 / 7.5 hours = $15.00 per hour
$122.50 / 5 hours = $24.50 per hour
Alastair earns more per hour
12. Taryn: 49 more hours ($735 / $15.00)
Alastaie: 30 more hours ($735 / $24.50)
You found how much money they charge per hour in 11 so use that to find how many hours it takes to earn $735.
