I will mark brainiest if you answer ty also you can answer one of them or both tysm i will mark brainliest for both
![I will mark brainiest if you answer ty also you can answer one of them or both tysm i will mark brainliest for both class=](https://us-static.z-dn.net/files/dcb/496cea4329bd8bc44d4bbf6b075ee178.png)
Step-by-step explanation:
a) The total cost C is given by
[tex]C = \$60n + \$40[/tex]
b) If the total cost is $400, then we can solve for the number of hours as
[tex]\$400 = \$60n + \$40 \Rightarrow \$360 = \$60n[/tex]
Solving for n, we get
[tex]n = \dfrac{\$360}{\$60} = 6\:\text{hrs}[/tex]