Question

The equation y = 55x + 85 describes the amount of money a plumber charges, where y is the total amount he charges and x is the number of hours he works. The table shows the total amount of money an electrician charges.

How much does each charge per hour?

Number of hours worked 1 2 4 7
Total amount charged 115 180 310 505

The plumber charges $_____per hour.
The electrician charges $_____per hour.

Answer 1

The plumber charges $55 per hour. The rate is equivalent to the slope of the line.
The electrician charges $65 per hour, because this is the amount the cost increases per hour.