Question

Mr.harris earns $12 per hour for 40 hours of work. He earns $18 per hour for hours worked over 40. How many hours did he work if he earned $642 ?

Answer 1

40 x 12 = 480
642 - 480 = 162
162/18 = 9

so he worked 40 hrs reg pay and 9 hours over time pay

Answer 2

12x +18y = 642
x = 40 hours (given)
12(40) + 18y = 642
480 + 18y = 642

18y = 642-480
18y = 162
y = 162/18 = 9