Answer:
he works 20 per week, so in a month, he will have 20*4= 80 hours, here 4 is the number of weeks in one month, and we have as information that he is paid for one hour $8.50, so you can do: 80*($8.50)= $680
Explanation:
(20hours)*(4 weeks)= 80hours
(80hours)*($8.50)= $680