Final answer:
Stephanie earns a) $1.50 more per hour compared to Marco.
Step-by-step explanation:
To calculate how much more Stephanie earns per hour compared to Marco, we need to find the difference between their wages per hour. Stephanie earns $10.50 per hour (represented as 10.50h) and Marco earns $9 per hour (represented as 9h). So, the difference in their wages per hour is:
Stephanie's wage - Marco's wage = 10.50h - 9h = 1.50h
Therefore, Stephanie earns $1.50 more per hour compared to Marco.