Direct Variation Quiz

What does the Direct Variation Equation look like?

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

• y=1344x

• y=100x

• $y=\frac{21}{4}x$

• $y=\frac{4}{21}x$

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?

• $\frac{2}{3}$

• 6

• $\frac{20}{3}$

• 7

Suppose y varies directly with x.
If y = 150 when x = 2, find y when x = 25.

• 300
• 75
• 1,875
• 12

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 direct 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 directly 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 = 0.25 x

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 x, and y is 84 when x is 16. Which equation represents this situation?

• y=1344x
• y=100x
• y=5.25x
• y=4/21x