Independent and Dependent Variables

Sarah is participating in a walkathon to raise money for local literacy programs. The amount of money Sarah will raise depends on the distance she walks.
m = the amount of money Sarah will raise
d = the distance Sarah walks
The following equation can be used to find the amount of money she will raise. 
m=75d
Which of the variables is dependent?

• m
• d
• 75
• Sarah

A student is planning an experiment to find out how the height from which he drops a ball affects how high the ball bounces. The dependent variable is the _____.

• Diameter of the ball
• Force acting on the ball
• Height that the ball bounces
• Height from which the ball is dropped

Samantha is bringing treats to her elementary school class on her birthday. The number of treats she brings in is based on the number of students in her class.
t = the number of treats
s = the number of students
The number of treats she will bring can be found using the equation 
t=3s+5
Which of the variables is independent?

• s
• t
• 3
• 5

In order to earn extra spending money, Dalton babysits children after school. The greater the number of hours he babysits, the more money he earns.
h = the number of hours Dalton babysits
m = the amount of money Dalton earns
Which of the variables is dependent?

• h
• m

The graph shows the distance traveled by a family on a road trip .  They will travel 25 miles each hour. Which statement is true about the situation?

• the independent variable is distance
• the independent variable is d=25 t
• the dependent variable is time
• the dependent variable is distance

The graph shows the cost of mailing a package based on its weight.  Which statement is true about the situation?

• The dependent variable is total cost
• The dependent variable is weight
• The independent variable is total cost
• The independent variable is cost of a package

Priya streams movies through a company that charges her a $5 monthly fee plus $1.50 per movie.  Her monthly movie cost can be found using the equation C=5+1.5m where C is the money it costs and m is the number of movies she rents. What is the dependent variable?

• the number of movies she rents
• the company that she rents from
• the money it costs
• There isn't one

Will practices at a batting cage.  The table shows the total cost based on the number of tokens purchased.  Which of the following is the independent variable in this situation?

• number of tokens
• total cost
• {1, 2, 3, 4}
• {7, 10, 13, 16}

Daisy is training for a marathon.  The amount of time spent running depends on how far she runs.  Which statement is true

• The dependent variable is the amount of time spent running, the independent variable is the miles run. 
• The dependent variable is miles run, the independent variable is the time spent running.
• The independent variable is her running shoes and the dependent variable is the flavor of gatorade she drinks
• The dependent variable is the weather and the independent variable is the time of day. 

The volume of a sphere is given by the formula V=4πr³, where V is the volume and r is the radius.  What is the dependent variable in this situation?

• V
• 4
• r
• π