Answer:
You will earn $15.75, $13.50, or $18 depending on how you are getting paid
Explanation:
If you are getting paid a flat rate not by the hour, then simply multiply $3.50 by 3.5 to get $15.75
If you are getting paid by the hour, and only by full hours, the you get $3.50 for the first, second, and third hour, but not for the fourth hour because it has only been a half hour, so only $13.50.
If you are getting paid for each hour that you start, then you get $3.50 for four hours, or $18.00 total