Question

A plumber charges a base fee for all service appointments. If a repair is needed, he adds a charge for each hour of labor. If the total cost, y, in dollars, of the plumber's x-hour repair visit is modeled by the equation y = 25x + 30, what could the 30 represent?

Answer 1

The base fee for all appointments is $30.

Explanation:

Step 1 :

Equation modelling the plumber's total cost = y = 25x + 30,

y = total cost in dollars

x = number of hours of repair.

Given that the plumber charges a base fee for the repair

Step 2 :

From the equation we can see that the co efficient of x is 25. As this component is dependent on x , this is the hourly charge added by the plumber.

So in case he works for 1 hour, the charge would be 25 * 1 = 25 dollars plus the base charge.

The second component in the model equation is 30. This is independent of any variable and indicates that this amount is charged irrespective f the number of hours worked. This is the fixed component.

Hence the base fee for all appointments is $30.

Step 3 :

Answer :

The base fee charged for all appointments is $30.