#### Explanation:

I think it's $12.5$ because I did $\frac{225}{18}$.

#### Explanation:

Divide $225$ by $18$ to calculate how much she earned in an hour:

$\frac{225}{18} = 12.5$ so Marie was payed $12.5 per hour. CHECK: $18 \times 12.5 = 225\$ is true, so we know our answer is correct.