Direct and Inverse Variation

Which table represents a direct variation?

• 
• 
• 
• 

Which equation represents an inverse variation?

• $y=-3x+5$

• $y=-2x$

• $y=\frac{x}{8}$

• $y=\frac{8}{x}$

Which equation represents a direct variation?

• $y=-\frac{1}{2}x+5$

• $y=-2x$

• $xy=25$

• $y=\frac{3}{x}$

Which set of ordered pairs represent a direct variation?

• {(1,12), (2, 6), (3, 4), (4, 3)}

• {(1, 3), (2, 3), (3, 3), (4, 3)}

• {(1, 9), (2, 7), (3, 5)}

• {(4, 2), (6, 3), (8, 4), (10, 5)}

Y varies directly to x. If y = 16 when x = 4, which equation represents this situation?

• $y=\frac{1}{4}x$

• $y=12x$

• $y=4x$

• $y=64x$

Y varies inversely to x. If y = 0.5 when x = 4, which equation represents this situation?

• $y=\frac{2}{x}$

• $y=4x$

• $y=2x$

• $y=\frac{x}{2}$

Ounces of medication vary directly with the weight of the patient. If a 120-pound adult requires 3 ounces of a medication, how many ounces would be needed for a 200-pound adult?

• 2

• 3

• 5

• 9

The point (2,4) is an element of direct variation. Which point is NOT an element of this variation?

• (0, 0)

• (4, 2)

• (1, 2)

• (3, 6)

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