# A plumber charges $75 for the first 30 minutes of each house call plus $2 for each additional minute that she works. The plumber charges Adam $113 for her time. For what amount of time, in minutes, did the plumber work?

##### 1 Answer

Aug 10, 2016

49 minutes

#### Explanation:

We can construct a formula for the plumber's fee.

The red 75 denotes the $75 that is charged for the first half hour.

Cost is $113 so

Can subtract 75 from both sides of the equation without changing anything about it:

Divide both sides by 2:

She worked 19 minutes over the first 30, so worked