Answer:
Part 1: At eight hours they both charge the same.
Part 2: Flush Plumbing charges the least
Explanation:
Part 1:
Flush Plumbing Co Equation: 50 + 10 h (h = hours)
Fire-in-the-hole Plumbing: 90 + 5h (h = hours)
50 + 10h = 90 + 5h
Solve the Equation:
5h = 40
h = 8
Part 2:
Plug in 7:
Flush Plumbing: 50 + 10 x 7 = 50 + 70 = $120
Fire-in-the-hole Plumbing: 90 +5 x 7 = 90 +35 = $125
Flush plumbing chargers the least
Hope this is helpful!