Direct and Indirect Proportions

If y is inversely proportional to x, and y = 15 when x = 3, what is the value of y when x = 5?

• y = 12

• y = 7

• y = 9

• y = 20

If y is directly proportional to x, and y = 10 when x = 5, what is the value of y when x = 8?

• 20

• 12

• 5

• 16

In a direct proportion, if x = 4 when y = 8, what is the value of y when x = 10?

• 15

• 5

• 20

• 25

Was the previous question an example of direct or indirect proportion?

• Direct proportion

• Indirect proportion

A recipe for pastry requires 160g of sugar to make 320g of pastry. How many grams of sugar will be needed to make 40g of pastry?

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 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

You can buy 4 tickets for $75 or 5 tickets for $94. Are the costs proportional?

• Yes

• No

The number of pencils sold varies directly as the cost. If 5 pencils cost $0.45, find the cost of 7 pencils.

• Direct

• Inverse

• Both

• None

Do the ratios form a proportion?

• Yes, they form a proportion.

• No, they do not form a proportion.