Grade 7 Algebra: Variables, Constants & Linear Functions

A store sells pencils for $0.50 each. If you buy x pencils, write an equation to represent the total cost. What is the constant in this equation?

• $0.75

• 0.50

• $0.25

• $1.00

Maria is saving money to buy a video game that costs $60. If she saves $5 each week, write an equation to represent her savings after w weeks. What are the variables and constants in this equation?

• S = 5w; Variables: w; Constants: 5

• S = 60 - 5w; Variables: S; Constants: 60

• S = 10w; Variables: w; Constants: 10

• S = 5 + w; Variables: S; Constants: 5

A car rental company charges a flat fee of $20 plus $0.15 per mile driven. Write an equation to represent the total cost C for driving m miles. Identify the variables and constants.

• C = 20 + 0.15m

• C = 15 + 0.15m

• C = 20 + 0.10m

• C = 20 - 0.15m

A gardener is planting flowers in rows. If he plants r rows with 10 flowers in each row, write an equation to represent the total number of flowers f. What are the variables and constants?

• f = r / 10; Variables: f; Constant: 10

• f = 10 - r; Variables: r; Constant: f

• f = r * 10; Variables: r; Constant: 10

• f = 10 + r; Variables: f; Constant: r

A school is organizing a field trip. Each student pays $15, and there are s students attending. Write an equation for the total amount collected T. Identify the variables and constants in your equation.

• T = s + 15

• T = 15 - s

• T = 15 / s

• T = 15 * s

A bike shop sells bikes for $200 each. If b bikes are sold, write an equation to represent the total sales S. What is the constant in this equation?

• 250

• 300

• 200

• 150

A recipe requires 2 cups of flour for each batch of cookies. If you want to make b batches, write an equation for the total amount of flour f needed. Identify the variables and constants.

• f = b

• f = 2b

• f = 2b + 1

• f = 4b

A concert hall has 500 seats. If x seats are sold, write an equation to represent the number of seats left y. What are the variables and constants in this equation?

• y = 500 - 2x; Variables: x (seats sold), y (seats left); Constant: 500 (total seats)

• y = x - 500; Variables: x (seats sold), y (seats left); Constant: 500 (total seats)

• y = 500 - x; Variables: x (seats sold), y (seats left); Constant: 500 (total seats)

• y = 500 + x; Variables: x (seats sold), y (seats left); Constant: 500 (total seats)

A book costs $12. If you buy b books, write an equation to represent the total cost C. Identify the constant in this equation.

• C = 10b; constant = 10

• C = 12b; constant = 12

• C = 12b + 5; constant = 5

• C = 12 + b; constant = 12

A factory produces 100 toys each hour. If h hours are worked, write an equation to represent the total number of toys T produced. What are the variables and constants in your equation?

• T = h + 100

• T = 50h

• T = 100 + h

• T = 100h