Modeling Costs: Identify Variables & Constants in Equations

A car rental company charges a flat fee of $50 plus $0.20 per mile driven. Write an equation to model the total cost (C) for driving m miles. Identify the variable and constant in your equation.

• C = 50 + 0.20m

• C = 0.20m - 50

• C = 50 + 0.50m

• C = 50 - 0.20m

Maria is saving money to buy a new phone that costs $300. If she saves $25 each week, write an equation to represent the number of weeks (w) it will take her to save enough money. Identify the variable and constant.

• 30w = 300

• 25w + 50 = 300

• 20w = 300

• 25w = 300

A gym charges a monthly membership fee of $40 plus $10 for each class attended. Write an equation to model the total cost (C) for attending c classes in a month. Identify the variable and constant in your equation.

• C = 40 + 10c

• C = 40c + 10

• C = 50 + 10c

• C = 10 + 40c

A bookstore sells notebooks for $3 each. If Sarah buys n notebooks, write an equation to model the total cost (C) of her purchase. Identify the variable and constant in your equation.

• C = 3n

• C = n + 3

• C = 3n + 1

• C = 3 + n

Tom is planning a party and has a budget of $200. If he spends $30 on decorations, write an equation to find out how much he can spend on food (F). Identify the variable and constant in your equation.

• F = 100

• F = 170

• F = 200

• F = 150

A phone plan costs $30 per month plus $0.10 for each text message sent. Write an equation to model the total cost (C) for sending t text messages in a month. Identify the variable and constant in your equation.

• C = 30 + 0.05t; variable: t, constant: 0.05

• C = 30 + 0.10t; variable: t, constant: 30

• C = 30t + 0.10; variable: C, constant: 0.10

• C = 0.10 + 30t; variable: t, constant: 0.10

A local bakery sells cupcakes for $2 each. If Emily buys c cupcakes, write an equation to model the total cost (C) of her purchase. Identify the variable and constant in your equation.

• C = 3c; variable: c, constant: 3

• C = c + 2; variable: C, constant: c

• C = 2 + c; variable: c, constant: 2

• C = 2c; variable: c, constant: 2

A taxi company charges a base fare of $5 plus $2 for each mile driven. Write an equation to model the total fare (F) for driving d miles. Identify the variable and constant in your equation.

• F = 5d + 2

• F = 5 + 2d

• F = 2 + 5d

• F = 2d + 5

A school is selling tickets for a concert at $15 each. If they sell t tickets, write an equation to model the total revenue (R) from ticket sales. Identify the variable and constant in your equation.

• R = 15t, where t is the number of tickets sold and 15 is the price per ticket.

• R = 15 + t, where t is the number of tickets sold and 15 is the total revenue.

• R = 20t, where t is the number of tickets sold and 20 is the price per ticket.

• R = 10t, where t is the number of tickets sold and 10 is the price per ticket.

Liam is saving for a video game that costs $60. If he saves $15 each week, write an equation to represent the number of weeks (w) it will take him to save enough money. Identify the variable and constant in your equation.

• 20w = 60; variable: w, constant: 20

• 15w = 60; variable: w, constant: 60

• 5w = 60; variable: w, constant: 5

• 10w = 60; variable: w, constant: 10