Interpreting Rate of Change

At what rate did the rain fall?

• 2 cm per hour

• ¹/₄ cm per hour

• ¹/₂ cm per hour

• 4 cm per hour

Charlie rented a moving truck. He paid a daily fee plus a per-mile fee to rent the truck. The equation below represents the daily amount Charlie paid for the truck if he drives it x miles.
y=0.5x+10
What does the slope of the graph of this equation represent?

• The daily fee for the moving truck

• The per-mile fee for the moving truck

• How much Charlie paid for the truck

• The number of miles he drove

Bob has $150 in his savings account and saves $40 per month.  Which equation represents the amount Bob has in his account after x months?

• y = 150 + 40

• y = 40x + 150

• y = 150x + 40

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

Sandra has a $20 itunes gift card and spends $3 each month.  Which equation can be used to find how much money Sandra has on her giftcard after x months?

• y = 3x + 20

• y = 3 + 20x

• y = -3x + 20

• y = -20x + 3

A man is climbing down from 100 feet high descending 30 feet per minute.

• y = - 30x + 100

• y = 100 + 30x

• y = 100x + 30

• y = 100x - 30

The temperature where Cally lives is 73℉ and is falling 2℉ per hour. Which of the following equations can be used to determine how many hours (x) it will take for the temperature to drop to 65℉?

• 73 - 2x = y

• 73 - 65 = 2x

• 65 - 2x = y

• 2x - 73 = y

Haylee is on page 219 of her library book. She reads at a pace of 1.5 pages per minute. Which of the following equations could be used to determine the total pages read (y) after a given number of minutes (x)?

• y = 219x + 1.5

• 219 = y +1.5x

• y = 1.5x +219

• y = 220.5x

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?

• y = 0.20x + 15

• y =15 (0.20x)

• y = 15 + x + 0.20

• y = 0.20 + 15x

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