Hi there! The answer is $465
The total cost can be found using the formula
[tex]15h + 40f[/tex]
To find the amount of money Ben Frank charges, we need to plug in the data from the question.
h = number of hours worked = 7
f = number of fixtures installed = 9
[tex]15 \times 7 + 40 \times 9 = 105 + 360 = 465[/tex]
Therefore, Ben Frank charges $465
~ Hope this helps you!