Linear Equations in Real World

A tub has 40 gallons of water in it and starts draining at a rate of 6 gallons per minute. Write an equation for the amount of water left in the tub.

• y = 6x + 40

• y = -6x + 40

• y = 6x - 40

• y = 40x - 6

A candle is originally 12 inches tall and burns a constant rate of 2 inches per hour. Write a formula for the height of the candle remaining.

• y = 2x + 12

• y = -2x + 12

• y = 12x - 2

• y = 12x + 2

To prepare for a recent road trip, Jill filled up her 19-gallon tank. She estimates that her SUV will use about three gallons per hour. Write an equation to model the scenario.

• y=19 – 3x

• y=19 + 3x

• y=3 - 19x

• y=3 + 19x

Bob's Plumbing charges $25 per hour plus an initial service fee of $40 for coming out to your house. Which equation models this situation?

• y = 25x + 40

• y = 40x + 25

• y = 25x

• y = 25x - 40

Amelia has $100 in her savings account and plans on saving $20 per week. Write an equation to represent this situation.

• y = 100x

• y = 20x

• y = 20x + 100

• y = 100x + 20

A fitness club opens with 80 members. Each month the membership increases by 15 members. Which equation represents the relationship between the number of months the club has been opened, x, and the total fitness club membership, y?

• y=15x

• y=15x+80

• y=x+15

• y=80x+15

You are visiting Baltimore, MD and a taxi company charges you a flat fee of $3.00 for using the taxi and $0.75 per mile.

Which of the following equations matches the situation?

• y = 3x + 0.75

• y = 0.75x + 3

• y = 3x - 0.75

• y = -3x + 0.75

You and a friend are playing a board game. Your final score x is 12 points less than your friend’s final score. Write and solve an equation to find your final score.

A discounted amusement park ticket costs $12.95 less than the original price p. The discounted ticket costs $44. Write and solve an equation to find the original price.

The balance of an investment account is $308 more than the balance 4 years ago. The current balance of the account is $4708. What was the balance 4 years ago?