Describe a real world situation that can be modeled by the equation y = 1/20x. be sure to describe what each variable represents.

For this case, the first thing we must do is define variables.
 We have then:
 x: number of minutes
 y: total cost
 We have then the following description:
 The gym in a city charges $ 1 for every 20 minutes of training a person does every day. Write an equation that models the problem.
 The equation that models the problem is:
 
 Where the slope of the line is:
 
 And it represents the cost of the gym for every 20 minutes of training.