STAAR 7.4a Constant Rate of Change

In a city, the average cost of electricity is $0.12 per kilowatt-hour. Which graph best represents this relationship?

• A

• B

• C

• D

A recipe for trail mix requires 1.5 cups of nuts for every cup of dried fruit. Create a graph to represent y, the number of cups of nuts required for x cups of dried fruit. Select two points on the coordinate grid. A line will connect the points.

A dog eats 1.25 cups of dog food twice a day. Which graph best represents this relationship?

• Graph A

• Graph B

• Graph C

• Graph D

An online game increases in number of users at a rate of 500 users each day. Which graph best represents the relationship between y, the number of users, and x, the number of days?

• A

• B

• C

• D

A student in a foreign language program learns 15 new words each week. Which graph best represents the relationship between x, the number of weeks the student has been in the program and y, the total number of new words the student has learned?

• F

• G

• H

• J

Natasha has a job putting letters in envelopes to be mailed. In 1 hour she put 42 letters in envelopes. Which equation best represents y, the total number of letters Natasha puts in envelopes in x hours if she continues at this rate?

• x = y + 42

• y = x + 42

• x = 42y

• y = 42x

Pamela rode her bike at a constant rate of 0.1 kilometer per minute. Which table represents y, the number of kilometers Pamela rode her bike in x minutes?

• F

• G

• H

• J

Which answer choice represents a person burning 90 calories by climbing 18 flights of stairs?

• A

• B

• C

• D

Cheddar cheese costs $4.25 per pound. Which equation best represents y, the total cost of x pounds of cheddar cheese?

• x = 4.25 + y

• x = 4.25y

• y = 4.25 + x

• y = 4.25x

The graph represents the linear relationship between the number of books Layla has read and the number of months she has been a member of a book club. Which of these statements is supported by the rate of change in this relationship?

• Layla read 2 books in the first 3 months she was a member of the book club.

• Layla read 3 books in the first 2 months she was a member of the book club.

• Layla read 3 books in the first 4 months she was a member of the book club.

• Layla read 4 books in the first 3 months she was a member of the book club.