Geoff charges $23.80 for 4 hours of swimming lessons. Anne charges $17.80 for 5 hours. To the nearest cent, how much more does Geoff charge per hour than Anne?

ANSWER

The required equation is



EXPLANATION

Let the equation of the line be


where

is the slope of the line. We substitute this value of the slope into the equation (1) to obtain,



Since the point (1,8) lies on the line, it must satisfy this equation.

We substitute the x and y value of the point into the equation(2) to get,



This simplifies to give us,



We solve for b to get,





We substitute the value of b back into equation (2) to get