Finding Slope and Writing Linear Equations Word Problems

The Roaming Cell Phone Company charges $15.00 per month plus $0.20 per minute of airtime usage.  If Juanita uses x minutes of airtime, what is an equation that can be used to determine her monthly cell phone bill (C)?

• C = 15 + 0.20x

• C =15 (0.20x)

• C = 15 + x + 0.20

• C = 0.20 + 15x

At Joe's Clown Car Rental Agency, renting a car costs $35 plus $0.75 for every mile it is driven.  What is an equation that can be used to find the number of miles, m, a vehicle was driven, if the total rental charge was $222.50?

• 222.5 = m(35 + 0.75)

• 222.5 = 35 + 0.75m

• 222.5 = 0.75 + 35m

• 222.5 = 0.75(m + 35)

A rental company at Best Bargain Rental costs $150 a week, plus $0.10 per mile.  Which equation represents the relationship between the number of miles (x) and the total cost in dollars (y) for a 2- week period?

• y = 2(150)(0.10x)

• y = 2(150) + 0.10x

• y = 150 + 2(0.10x)

• y = 2(150 + 0.10x)

Bob's Plumbing charges $15 per hour plus a service fee of $40 for coming out to your house. Which equation models this situation?

• y = 15x + 40

• y = 40x + 15

• y = 15x

• y = 15x - 40

A plumber charges $25 for a service call plus $50 per hour of service. What information is given and what equation should you use?

• A slope and a y - intercept are given; use y = mx + b.

• A slope and a y - intercept are given; use y - y1 = m(x - x1).

• Two points are given; use y - y1 = m(x - x1).

• Two different items that add to a total are given; use Ax + By = C

For babysitting, Nicole charges a flat fee of $3, plus $5 per hour. What information is given and what equation should you use?

• A slope and a y - intercept is given; use y = mx + b.

• A slope and a y - intercept is given; use y - y1 = m(x - x1).

• Two points are given; use y - y1 = m(x - x1).

• Two different items that add to a total are given; Ax + By = C

You and your friends go to the movies and purchase some popcorn and Pepsi. Popcorn is sold for $4.99 per bag and Pepsi is sold for $1.99 per bottle. You each chip in to pay $24.92. Write an equation to represent the given situation.

• y = 1.99x + 4.99

• y = 4.99x + 24.92

• y - 1.99 = 4.99(x - 24.92)

• 1.99x + 4.99y = 24.92

A caterer charges $100 to cater a party for 10 people and $175 for 25 people. Write an equation for the given situation.

• y = 25x + 100

• y - 100 = 5(x - 10)

• y - 175 = 10(x - 25)

• 100x + 175y = 35

When an individual rides in a taxi for 20 miles, it costs them $21. Another individual rides in the same taxi for 30 miles and pays $26.50. What information is given and which equation should you use?

• A slope and y - intercept is given; use y = mx + b.

• A slope and y - intercept is given; use y - y1 = m(x - x1).

• Two points are given; use y - y1 = m(x - x1).

• Two different items that add to a total are given; use Ax + By = C.

Suppose that the water level of a river is 34 feet and that it is receding at a rate of 0.5 foot per day. Write an equation to represent the given situation.

• y = -0.5x + 34

• y = -34x + 0.5

• y - 34 = 0.5(x - 1)

• 34x - 0.5y = 33.5