Direct and Inverse Variation Problems

If y varies inversely as x, and y =8 when x=5, find y when x = 4.

• 8

• 5

• 10

• 12

If y varies directly as x, and y = 6 when x = 15, find y when x = 2

• 4/5

• 3

• 3/2

• 4

If y varies directly as x, and y = 4 when x =6, find y when x = 5.

• 6/5

• 3/4

• 5/2

• 10/3

If y varies directly as x³, and y = 3 when x = 2, find x when y = 24

• 2

• 3

• 4

• 5

e varies jointly as f and g, and e = 24 when f = 3 and g = 2. Find the constant of variation (k)

• 1

• 2

• 3

• 4

The electrical current, in amperes, in a circuit varies directly as the voltage. When 15 volts are applied, the current is 5 amperes. What is the current when 18 volts are applied?

• 19

• 21

• 23

• 25

The volume of a cone varies jointly as its height, and the square of its radius. If a cone with a height of 8 centimeters and a radius of 2 centimeters has a volume of 33.5 cm3 , what is the volume of a cone with a height of 6 centimeters and a radius of 4 centimeters?

• 50

• 100.5

• 120.2

• 95

The stopping distance of a car after the brakes have been applied varies directly as the square of the speed r. If a car, traveling 60 mph can stop in 200 ft, how fast can a car go and still stop in 72 ft?

• 34

• 35

• 36

• 37

The intensity of a television signal varies inversely as the square of the distance from the transmitter. If the intensity is 25 W/m² at a distance of 2 km, how far from the transmitter are you when the intensity is 2.56 W/m² ?

• 5.5

• 5.75

• 6

• 6.25

The number of kilograms of water in a human body varies directly as the mass of the body. A 96-kg person contains 64 kg of water. How many kilo grams of water are in a 60-kg person?

• 40

• 45

• 50

• 55