What is the cost of having a plumber spend h hr at your house if the plumber charges 20 for coming to the house and 25 per hour for labor?

The total cost of having a plumber spend half an hour (0.5 hours) at your house includes the service charge and labor. The service charge is $20, and the labor cost for 0.5 hours is $25 x 0.5 = $12.50. Therefore, the total cost would be $20 + $12.50 = $32.50.