Question

The costs of a fill-up and a car wash for three different customers are shown in the table. Write an equation for the function in slope-intercept form. Then, find the cost of a fill-up and a car wash for a customer with a truck whose tank size is 25 gallons.

Answer 1

The Linear Equation for the given problem is; f(x) = 1.90x + 3.50

Cost for truck = $51.00

How to find the Linear Equation?

The slope of the equation is given by the formula;

Slope = (y₂ - y₁)/(x₂ - x₁)

Using the coordinates (8, 18.7) and (12, 26.30), we have;

Slope = (26.3 - 18.7)/(12 - 8)

Slope = 1.90

Equation of line is;

y - 18.7 = 1.9(x - 8)

y = 1.9x - 15.2 + 18.7

y = 1.9x + 3.5

For a 25 gallon size;

Cost = 1.9(25) + 3.5

Cost = $51