Answer:
There were 15 installments of the roof.
Step-by-step explanation:
We are given the following information in the question:
Total number of invoice = 65
Cost of installation = $490
Cost of repair = $68
Total cost = $10,750
Let x be the number of installments and y be the number of repairs.
Then, we can write the following equations:
[tex]x + y = 65\\490x + 68y = 10750[/tex]
Solving the two equations in two variables, we get:
[tex]68x + 68y = 4420\\490x + 68y = 10750\\490x - 68x = 10750 - 4420\\422x = 6330\\x = 15\\\text{Putting value of x in one of the equation}\\15 + y = 65\\y =65-15 = 50[/tex]
Thus, there were 15 installments and 50 repairs of the roof.
