$92/week is the amount of money you gained from work combined with your $20/week allowance money.
92 - 20 = 72 (total money made per week subtract allowance money leaves money made from work)
Thus, you make $72/week at your part time job.
You work a total of 9 hours. (3hrs on Fri & 6hrs on Sat added together)
72/9 = 8 (total amount of money made divided by the 9 hrs you worked for - gives amount of money you make per hour)
Thus, you make $8/hr at your part time job.
