Direct and Inverse Variation

The gas pressure in a chamber varies directly with the temperature in the chamber. If the pressure in the chamber is 150 atmospheres (atm) when the chamber is at 50 degrees, what is the pressure in the chamber when the temperature of the chamber is 75 degrees?

• 175 atm

• 200 atm

• 225 atm

• 275 atm

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

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

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)