### Home > PC3 > Chapter 13 > Lesson 13.3.1 > Problem 13-109

At noon, John is

Express the distance of John’s car

*north*of Cactus Junction as a function of time.How far away is John from Cactus Junction now?

A position north of Cactus Junction should be positive, so what value would a position south of Cactus Junction beWhat expression describes his distance?

Express the distance of Amy’s car

*east*of Cactus Junction as a function of time.Follow the example for John's distance.

Calculate the distance between John and Amy at the time

hours after noon.Use the distance formula.

When are John and Amy’s cars closest together? (Hint: Graph the distance equation you found in part (c).)