Identifying Dependent and Independent Variables

What is the independent variable?

The number of students in a class, s, and the number of desks needed, d

• number of students in a class, s

• number of desks needed, d

• number of desks in a class, d

• number of students needed, s

What is the dependent variable?

The number of students in a class, s, and the number of desks needed, d

• number of students in a class, s

• number of desks needed, d

• number of desks in a class, d

• number of students needed, s

What is the independent variable?

The number of candles on a birthday cake, c, and that person's age, a

• number of candles on a birthday cake, c

• that person's age, a

What is the dependent variable?

The number of candles on a birthday cake, c, and that person's age, a

• number of candles on a birthday cake, c

• that person's age, a

A phone company charges a base rate of $40 a month for service. The user is charged $0.20 a minute for every minute used. The total amount charge to the customer, p, for any number of minutes, m, can be represented by the function
p = .2m + 40.
What is the dependent variable?

• The # of minutes used

• The base rate of $40

• The total amount charged to the customer

• The $0.20 per minute

Elizabeth hired a cleaning service to clean her house. To find C, the total cost of cleaning her house, she used the following equation.

C = 7.5x + 25

What is the dependent variable for the equation?

• 7.25

• 25

• C

• x

The dependent variable is:

• x

• y

In the equation y = 2x - 4, what is the dependent variable?

• 2x

• x

• -4

• y

Elizabeth hired a cleaning service to clean her house. To find C, the total cost of cleaning her house, she used the following equation.

C = 7.5x + 25

What is the dependent variable for the equation?

• 7.25

• 25

• C

• x

What is the dependent variable in the equation y = 3x - 2?

• y

• x

• -2

• 3x