A plumber's arrives and includes the cost of parts and labor. The total for the bill is $458 for the job. The cost of parts was 271 and the cost of labor was $68 per hour. Find the number of hours labor
h = (458 - 271) / 68
To find the number of hours of labor, we need to subtract the cost of parts from the total bill and then divide the remainder by the cost of labor per hour.
Total bill - Cost of parts = Cost of labor
$458 - $271 = $187
Cost of labor / Cost per hour = Number of hours of labor
$187 / $68 = 2.75 hours
Therefore, the plumber worked for approximately 2.75 hours.