Direct Variation
Inverse Variation
Joint Variation
Word Problems
Word problems 2
100

Write an equation:

a varies directly with b.

What is a = kb?

100

Write the equation:

y varies inversely with x

y=k/x

100

Write the equation:

m varies jointly with b, h and c

What is m = kbhc?
100

The time, t, it takes to travel a certain distance varies directly with the speed, s.  Write the variation equation if t = 8 hours and s = 80 miles per hour.

What is 

t = 640/s

100

The time (T) required to do a job varies inversely as the number of people (P) working.  It takes 8 hours for 6 bricklayers to build a park wall.  

  • Solve for the constant and write an inverse variation equation. 

What is 

T = 48/p

200

Write the equation:

m varies directly with n.

What is m = kn?

200
Write the equation:

j varies inversely with the square of n.

What is 

j=k/n^2

200

Write the equation:

n varies directly with p and inversely with the cube of c.

What is 

n=(kp)/c^3

200

The time, t, it takes to travel a certain distance varies directly with the speed, s.  Write the variation equation if t = 8 hours and s = 80 miles per hour.  Use your equation to find out the time it takes for a trip if you are traveling 50 miles per hour.

What is 12.8 hours?

200

The time (T) required to do a job varies inversely as the number of people (P) working.  It takes 8 hours for 6 bricklayers to build a park wall.  

  • How long will it take 10 bricklayers to complete the job?

What is 4.8 hours?

300

P varies directly with q.  If p is 75 and q is 5, what is the constant of variation?

What is 15?

300

W varies inversely with q.  If w is 3 and q is 12, what is the value of the constant of variation?

What is 36?

300

Q varies jointly with a, b and c.  When a = 5, b = 3 and c = 2, Q is 150.  What is the value of the constant of variation?

What is k=5?

300

George’s income varies directly with the number of hours he works.  Thomas worked 50 hours last week and made $800.  

  • Solve for the constant and write a direct variation equation.

What is I = 40h?

300

The volume of a prism varies jointly as its width and height.  A prism has a height of 6 inches and a width of 3 inches and has a volume of 162 cubic inches.  

  • Solve for the constant and write a joint variation equation.

What is V = 9hw?

400

P varies directly with q.  If p is 75 and q is 5,write the variation equation.

What is p = 15q?

400

W varies inversely with q.  If w is 3 and q is 12, write the variation equation.

What is 

w=36/q

400

Q varies jointly with a, b and c.  When a = 5, b = 3 and c = 2, Q is 150.  Write the variation equation.

What is Q = 5abc?

400

Your score on a quiz varies directly with how many questions you answer correctly. If you got a 90 on your quiz and you got 30 questions right, write an equation for this relationship.

What is y = 3x?

400

The volume of a prism varies jointly as its width and height.  A prism has a height of 6 inches and a width of 3 inches and has a volume of 162 cubic inches. What is the volume of a prism with a height of 9 inches and a width of 4 inches?

What is 324 cubic inches?

500

P varies directly with q.  If p is 75 and q is 5, find the value of P when q is 8.

What is 120?

500

W varies inversely with q.  If w is 3 and q is 12, find the value of w when q is 9.

What is 4.

500

Q varies jointly with a, b and c.  When a = 5, b = 3 and c = 2, Q is 150. Q is 3000 when a is 10 and c is 5.  Find b.

What is 12?

500

The time, T, to travel a fixed distance varies inversely with the rate, R, of travel. If T=4 hr. and R=20 mi/hr. , find T when R=50 mi/hr.

What is T= 1.6 hours?

Hint - k = 80

500

The time, t, it takes to travel a certain distance varies inversely with speed, s.  If t = 8 hours and s = 70 mi/hr, how long will it take if you are traveling 80 mi/hr?

What is 7 hours?