Answer:
8 hours
$480
Step-by-step explanation:
Let us assume the hours be x
There should be two equations
For Plumber A = 60x
For Plumber B = 40 + 55x
Now in order to considered the cost to be the same we equate these two equations
60x = 40 + 55x
5x = 40
x = 8 hours
Now the total cost for plumber A is
= 480
And, the total cost for plumber B is
= 40 + 55(8)
= 480
hence, the total cost is $480