Direct and Inverse Variation

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

Y varies directly with x, and y is 84 when x is 16. Which equation represents this situation?

• y=1344x

• y=100x

• y=5.25x

• y=4/21x

If y = 15 when x = 12 find y when x = 32.

• 40

• -40

• 5

• -5

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 directly with the square of x.  If y=40 when x=4, find y when x = 7

• 17.5

• 70

• 122.5

a varies inversely as the square of b. If a is 1 when b is 3, find a when b is 5. 

• 0.36

• 9

• 25

• 36

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