Given:
Mary is paid $12 per hour at her weekend part-time job.
She earns an average of $132 each weekend, but her earnings can vary by $36.
To find:
The inequality for number of hours.
Solution:
Let h be the number of hours Mary could work in one weekend.
Total earning for h hours = $12h
She earns an average of $132 each weekend, but her earnings can vary by $36. So,
![132-36\leq \text{Total earning}\leq 132+36](https://img.qammunity.org/2021/formulas/mathematics/high-school/ql4rd5vrcjpfu631s8tcwtqz2gr28mpcf2.png)
![96\leq \text{Total earning}\leq 168](https://img.qammunity.org/2021/formulas/mathematics/high-school/a0rla4c2o9jv1s55tdg2m3qjd43d5ev138.png)
![96\leq 12h\leq 168](https://img.qammunity.org/2021/formulas/mathematics/high-school/qtkdtaz0gufzluxl3zikxvxg0edsknkgz3.png)
Divide all sides by 12.
![(96)/(12)\leq (12h)/(12)\leq (168)/(12)](https://img.qammunity.org/2021/formulas/mathematics/high-school/g3easdethavh0bjbvr7696gm7pumb7ttop.png)
![8\leq h\leq 14](https://img.qammunity.org/2021/formulas/mathematics/high-school/3x300auvio559t7xg1y3bjpvzyzy7qzwb3.png)
Therefore, the correct option is D.