You and your friends are at an amusement park. Some of you have not yet decided whether or not you want to go. If tickets cost $20 each, write the amount (in dollars) that you will spend as a function of the number of tickets you buy. Let *t* represent one ticket, and* c* represent the total cost in dollars.

Each ticket costs $20. This means that for every one of you who goes in, the total cost increases by $20. This is represented by the equation* c* = 20*t.*