Let h be the amount of hours that the life jackets and the paddle boat are used.
Since the two friends must pay $20 for every hour, then the amount charged for h hours is:
![20h](https://img.qammunity.org/2023/formulas/mathematics/college/ei33xv8074fo2m167gwbj4rpt5kjs87p67.png)
On the other hand, they must pay a onetime fee of $7 additional to the cost for using the equipment for h hours. Then, add 7 to the expression 20h to find the total cost:
![7+20h](https://img.qammunity.org/2023/formulas/mathematics/college/ebnmtoe9mzlgxe626s7g5jx3acla8snu5m.png)
Therefore, the expression that represents the total cost to rent the life jackets and paddle boat for h hours, is:
![20h+7](https://img.qammunity.org/2023/formulas/mathematics/college/6f370x0cv2iua4lc0ievnvzrttop078x7w.png)