Give the step-by-step reasoning process and then the final answer. The Donaldsons pay $15 per hour for babysitting. The Merck family pays $18 per hour and the Hille family pays $20 per hour for babysitting. Layla babysat for the Donaldsons for 7 hours, the Merck family for 6 hours and the Hille family for 3 hours. How many dollars did Layla earn babysitting?
Donaldsons pay $15 / hour = 15 * 7 = $105. The Mercks pay $18 / hour = 18 * 6 = $108. The Hilles pay $20 / hour = 20 * 3 = 60. The total amount Layla earned is 105 + 108 + 60 = 273. Layla earned $273 for babysitting.
The final answer: 273.