A utility company charges its residential customers a flat fee for electricity plus 8 cents for each kilowatt-hour (kWh) of electricity used. Last month, a customer used 400 kWh of electricity, and her total bill was $35. Notice that the bill is in units of dollars and the cost per kWh is given in cents. What do you need to do to account for that?
- Write an equation of the line that describes the relationship between the customer’s monthly bill (call it y) and the amount of electricity used (call it x).
- What does the slope of this line mean?
- What does the intercept mean?
- The following month, the customer used 550 kWh of electricity. Using the linear equation from # 1 above, find out how much her bill will be.