Proportional Relationships

Three friends are buying seashells at the gift shop on the beach. Melanie buys 2 seashells for​ $0.80. Rosi buys 5 seashells for​ $2.00. Carlos buys 4 seashells for​ $1.60. Which graph represents the situation?

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Error Analysis: You and a friend look at the graph. Your friend incorrectly says the constant of proportionality of y to x is 1/18. Find the correct constant of proportionality. What is your​ friend's likely​ error?

• Your friend found x/y.

• Your friend found x−y.

• Your friend found x•y.

• Your friend found x+y.

In a certain​ city, there are two stores where you can rent DVDs. The table shows the cost y in dollars to rent x DVDs at store A. The graph represents the cost at store B. At which store is the cost of renting DVDs the​ least and what is the constant of proportionality?

• Store A: $3.15

• Store A: $3.20

• Store B: $3.20

• Store B: $3.15

The graph shows the relationship between the distance a taxi travels and the cost of the taxi ride. Is the relationship​ proportional? Explain. What is true about the graph?

• The relationship is not proportional because the graph does not pass through the origin.

• The relationship is not proportional because the graph is not a straight line.

• The relationship is proportional because the cost increases as the distance increases.

• The relationship is proportional because the graph is a straight line.

You bike 11.2 miles in 1.4 hours at a steady rate. What equation represents the proportional relationship between the x hours you bike and the distance y in miles that you​ travel?

• 9

• 8

• .125

• .135

The graph shows a proportional relationship between a​ family's distance from home and the time they spent driving. What is the constant of​ proportionality? What does the point​ (1,49) represent?

• The distance to the destination.

• The time driven on the vacation.

• 49 hours and being 1 mile from home.

• 1 hour and being 49 miles from home.

A recipe calls for 3 ounces of flour(x) for every 2 ounces of sugar(y). Find the constant of proportionality.

• 2/3

• 3/2

• 5

• 6

An airplane on autopilot took 5 hours to travel​ 3,475 kilometers. What is the unit rate for kilometers per​ hour?

• 735

• 695

• 17,375

• .0014

Three friends are buying seashells at the gift shop on the beach. Melanie buys 2 seashells for​ $0.80. Rosi buys 5 seashells for​ $2.00. Carlos buys 4 seashells for​ $1.60. What is the constant of proportionality if one exists?

• $0.40

• $0.80

• $1.60

• Not a proportional relationship

Write this rate as a unit rate: You run a 5k (3.1 miles) in 28 minutes.

The unit rate is minute miles.

• .54

• .11

• 9

• 10