Answer :

(# hours per day) * (total days worked)= (total number of hours worked)
(total hours) * ($ amount earned per hour)= (total amount earned)= $581.25

(6.2) * (5)=31
(31) * (18.75)= 581.25
so  6.2 hours per day for 5 days
6.2 times 5=31 hours total
and 18.75 per hour

31 times 18.75=581.25

he earned $581.25