ORCA Unit 8: Modeling & Data Analysis

Which of the following represents direct variation?

• y = kx
• y = k/x
• y = x/k
• y = mx + b

Which of the following represents indirect variation?

• y = kx
• y = k/x
• y = x/k
• y = mx + b

 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

The width of a rectangle varies inversely with its length.  If the width is 6 when the length is 24, give an equation that shows the relationship.

• y = 4x
• y = 144x
• y = 4/x
• y = 144/x

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

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

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

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

• 17.5
• 70
• 122.5

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

Is the following graph direct, inverse, or neither?

• Direct
• Inverse
• Neither