Rate of Change

Sonya has $40 in her lunch account and pays $2 each day to eat lunch. Which equation can be used to find the amount of money Sonya has left on her account after x days?

• y = 40 + 2x

• y = - 2x + 40

• y = 2 + 40x

• y = 2 - 40x

Which of the following situations could be described by the equation y= -25x + 120

• There are 120 people in the football stadium, and 25 more are entering each hour.

• A plumber charges $25 for a house call and $120 per hour.

• A teacher has 120 students. Her third period has 25 students

• There are 120 gallons of water in a tank. It releases water at a rate of 25 gallons per minute

The local service center advertises that it charges a flat fee of $50 plus $8.25 per mile to tow a vehicle. Write an equation that represents the total cost (C) of a service for m miles of towing.

• M = 8.25c + 50

• C = 50m +8.25

• y = 50x + 8.25

• C = 8.25m + 50

Find the equation of the line in the graph.

• y = 2x + 5

• y = -2x + 5

• y = 5 + 2x

• y = - x + 5

A man is climbing down from 150 feet high descending 27 feet per minute.

• y = -27x + 150

• y = 27x - 150

• y = 150x + 27

• y = 150x - 27

What is the rate of change for the following graph?

• 80

• 20

• 40

• 160

Find the rate of change.

• -2 minutes per gallon

• -20 minutes per gallon

• -2 gallons per minute

• -20 gallons per minute

Mr. K is starting his own car club, there is a $30 join up fee and a $5 monthly fee. What is the rate of change in this situation?

• 30

• 5

• -5

• not enough information

A man is climbing down from 100 feet high descending 30 feet per minute. What is the rate of change in this situation?

• -30

• 30

• 100

• -100

What does the slope represent?

• $2 per mile drive

• $.50 per mile driven

• 2 miles driven per $1

• 1 mile driven per $2