Direct and Inverse Variation

• direct variation
• inverse variation
• joint variation
• none of these

Question: What is the type of variation?

• direct variation

• inverse variation

• joint variation

• none of these

Suppose y varies directly as x.
If  y = 22.5 when x = 15, find y when x = 20.

• 1.5

• 337.5

• 30

• 16.875

Which of the following represents indirect variation?

• y = kx

• y = k/x

• y = x/k

• y = mx + b

The Height of a wave in California varies directly with the seconds that pass by.  At 4 seconds, the wave is 6 feet high.  How many seconds will give you a wave that is 10 feet high? 

• y = 2/3x

• 6

• 6.6

• 7

The number of kilograms of water in a person’s body varies directly as the person’s mass.  A person with a mass of 90 kg contains 60 kg of water.  How many kilograms of water are in a person whose mass is 75 kg?

• 50 kg water

• 72 kg water

• 94 kg water

• 150 kg water

The interest received on a savings account varies directly with the amount deposited. Daniel received $55.35 in interest on $1230 he deposited. How much interest would Daniel have received if he had deposited $2000 into his account?

• 34.04

• 90.00

• 1,285.35

• 44,444.44

Which equation represents a direct variation?

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