Chloe is driving back home from college for summer vacation. She fuels up her gas tank and then drives for a certain amount of time before passing a roadside attraction. She drives on without stopping, and 3 hours after leaving her college, she has driven 120 miles past the attraction. Seven hours after leaving her college, she has driven 400 miles past the attraction. Write a linear equation in one variable for the distance Chloe covers in hours, and describe the domain of the linear equation. Assuming that Chloe travels at a constant speed without stopping, use the equation to determine her speed. Then, determine how far she had traveled before she passed the roadside attraction.

Name a dependent variable and an independent variable based on the given data.

Write ordered pairs for the data in the problem based on the identified variables.

Write an equation for the speed in terms of the distance and time.

Use the two ordered pairs from step 2 and the formula for the slope of a one-variable equation, , to find the rate.

Use the point-slope formula, , to write the linear equation in one variable.

Find the value of when .

Interpret the results based on the information given in the problem to determine how far Chloe drove before passing the roadside attraction.

This applet is provided by Walch Education as supplemental material for their mathematics programs. Visit www.walch.com for more information.