Question

Lexus skateboards from his house to school 4 miles away. It takes him 20 minutes.

Assume that Lexus skateboards at a constant rate.
Part A
Write an equation to represent the number of miles, m, that Lexus can skateboard in t minutes.

Answer 1

I used the equation y=4x+20.

Answer 2

`\displaystyle m = (1)/(5)\cdot t`

Explanation:

Proportional Model

The number of miles m that Lexus can skateboard in t minutes can be modeled by:

m = kt

It's given that Lexus skateboard from his house to school for a distance of m=4 miles in t=20 minutes.

Substituting:

4 = k.20

Dividing by 20

`k=(4)/(20)`

Simplifying:

`k=(1)/(5)`

This produces the model

`\displaystyle m = (1)/(5)\cdot t`