Direct Inverse Variation

As the speed of a train increases, the amount of time it takes to arrive at its destination decreases. What type of variation exists between the speed of the train and amount of time?

• Direct Variation

• Inverse Variation

• Neither

• Not enough information

The width of a rectangle varies inversely with its length. If the width is 4 when the length is 18, what is the width when the length is 8?

• 4

• 5

• 9

• 12

The width of a rectangle varies inversely with its length.  If the width is 6 when the length is 24, give an equation that shows the relationship.

• y = 4x

• y = 144x

• y = 4/x

• y = 144/x

Y is directly proportional to the square of z and inversely proportional to w.

• y=kz²/w

• y=kz/w

• y=w/kz²

• y=w/kz

Y varies inversely with x, and y is 0.5 when x is 4. Which equation represents this situation?

• y=2x

• y=2/x

• y=4x

• y=x/2

If x and y are in an inverse variation then which of the following is correct?

• x - y = constant

• x + y = constant

• xy = constant 

• x⁄y is constant 

y varies directly as the square of x and indirectly with z. If y is 8 when x is 4 and z is 6, find y when x is 8 and z is 4.

• 3

• 12

• 48

• 64

Which of the following represents indirect variation?

• y = kx

• y = k/x

• y = x/k

• y = mx + b

Is the given table a direct or inverse variation? What is the constant of variation?

• Direct, 12

• Inverse, 12

• Direct, 1/12

• Inverse, 1/12

Which of the given graphs is a direct variation?

• A

• B

• C

• D