Earning rate (earning per hour) =
Money earned per 1 hour = = $8.5 per hour
So the earning rate = $8.5 per hour.
\How to ensure your answer?
\To verify the correctness of the answer you can perform below step.
Cheque: \ \
\Earning rate = $8.5
\Money earned = earning rate × hours spent
\Money earned for 10 hours = earning rate × hours spent
\= $8.5 × 10
\ = $85
Earning rate = $8.5 per hour.
\