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.