Add up the hours.
1 3/4 + 2 3/4 + 1 5/12
Convert to improper fractions:
7/4 + 11/4 + 17/12
Convert 7/4 and 11/4 into denominators of 12:
21/12 + 33/12 + 17/12
Add the numerators:
71/12
Convert to mixed number:
5 11/12
Multiply by 10.5:
5 11/12 * 10.5 = 62.125
So he earned approximately $62.13