Practice Dependent vs Independent Variables in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The independent variable is chosen freely as input; the dependent variable's value is then determined by the function rule.

You choose the input (independent), and the function gives the output (dependent).

Showing a random 20 of 50 problems.

Example 1

hard
In y=12xy = \frac{12}{x}, describe how the dependent variable responds as the independent variable triples.

Example 2

medium
Given y=3xโˆ’1y=3x-1, find the dependent value when the independent value is 4.

Example 3

medium
On a graph, which axis typically shows the independent variable?

Example 4

easy
In the equation d=60td = 60t (distance = speed ร— time), which is dependent?

Example 5

easy
In A=ฯ€r2A = \pi r^2, what is the independent variable?

Example 6

medium
In x=5โˆ’2yx=5-2y, if yy is independent, express the dependent variable explicitly.

Example 7

easy
A water tank fills at a constant rate, V=5tV = 5t (liters at time tt minutes). Which is dependent?

Example 8

easy
In y=4xโˆ’7y = 4x - 7, name the dependent variable.

Example 9

medium
A taxi charges 3plus3 plus 2 per mile: C=3+2mC=3+2m. Identify both variables and their roles.

Example 10

medium
In the data table input 1,2,3 โ†’ output 2,4,6, name the variables.

Example 11

challenge
A circle's area depends on radius. If the radius is the independent variable, find the rate-style ratio Ar2\frac{A}{r^2} and explain.

Example 12

challenge
Two quantities satisfy y=mxy=mx for unknown fixed mm. Using the point (2,6)(2,6), find mm, then state which symbol is the parameter.

Example 13

medium
A scientist plots height versus age. Which axis holds age?

Example 14

challenge
In P=kVP=\frac{k}{V} (fixed kk), describe how the dependent variable responds as the independent one doubles.

Example 15

medium
If yy depends on xx via y=โˆ’2x+6y = -2x + 6, what happens to yy when xx increases by 11?

Example 16

challenge
A car's stopping distance is d=0.05v2d = 0.05 v^2 in meters. If a driver doubles their speed, by what factor does the dependent value dd grow?

Example 17

medium
For a table with inputs 1,2,3,41, 2, 3, 4 giving outputs 5,8,11,145, 8, 11, 14, write the linear rule with xx independent.

Example 18

medium
A coffee shop's daily revenue RR depends on customers nn: R=4.5nR = 4.5 n. Find nn when R=270R = 270.

Example 19

medium
A phone plan costs C=30+0.10mC = 30 + 0.10 m dollars, where mm is minutes used. Identify both variables and find CC when m=200m = 200.

Example 20

easy
In h=2+3dh = 2 + 3d where dd is days, find the dependent value when d=4d = 4.