Linear Equations Applications

Ex #1: The base pay of a water-delivery person is $210 per week. He also earns 20% commission on any sale he makes.

a) Write an equation that relates his total earnings to his sales.

b) What is his total earnings if he sold $200 of water?

c) How much did he sell if his total earnings was $240?

Ex #2: A dog kennel charges a base rate of $15 and $5 per day.

a) Write an equation for the total cost of putting a dog in the kennel for d days.

b) How much would it cost to have your dog in the kennel for 12 days?

c) How many days did a customer leave their dog at the kennel if the total cost was $$50?

Ex# 3: The freshman class holds a car wash to raise money. A local merchant donates all of the supplies. A wash costs $5 per car and $6.50 per SUV. The class made $800 on the car wash.

a) Write an equation that relates the number of cars washed and the number of SUVs washed.

b) How many SUVs were washed if 95 cars were washed?

c) How many cars were washed if 100 SUVs were washed?

Ex #4: A tire dealer sells Supreme tires for $24 each and Prestige tires for $56 each. During one week, the sales for both tires totaled $2688.

a) Write an equation that relates the number of Supreme tires sold and the number of Prestige tires sold.

b) How many Prestige tires were sold if 35 Supreme tires were sold?

c) How many Supreme tires were sold if 18 Prestige tires were sold?

Summary1. Define your variables (let statements)

2. Write a linear model / equation

3. Solve the problem

4. Answer the question with words!

Summary (cont.)

• Slope Intercept Form of a Line: y = mx + b– Use when a rate and a “starting point” are given– Can be expressed as a function

• Standard Form of a Line: Ax + By = C– Use when two independent rates are given– This form is not in function form