7th Grade Math

270 Proportions and Similarity

ESTIMATION Estimate the unit price for each item. Justify your answers.

25.

OrangeJuice

2 qt

$2.49

26.

Apples

5 lb

$1.89

27.

Pineapple

Chunks

$1.13

28. RECIPES A recipe that makes 10 mini-loaves of banana bread calls for
    1 _^14 cups flour. How much flour is needed to make 2 dozen mini-loaves
    using this recipe?

2929 SPORTS Use the information at the left.

a. The Boston Marathon is 26.2 miles long. What was the average speed

of the record winner of the wheelchair division? Round to the nearest

hundredth.

b. At this rate, about how long would it take this competitor to complete

a 30-mile race?

30. MONEY Suppose that 1 euro is worth $1.25. In Europe, a book costs
    19 euros. In Los Angeles, the same book costs $22.50. In which location
    is the book less expensive?


31. ANIMALS Use the graph that shows

12

Heartbeats

60

80

100

120

40

0

Time (min)

Brown Bear Heart Rates

20

(1.5, 90)

Hibernating

Active

(1.5, 18)

(2, 120)

(2, 24)

the average number of heartbeats

for an active adult brown bear and

a hibernating brown bear.

a. What does the point (2, 120)

represent on the graph?

b. What does the point (1.5, 18)

represent on the graph?

c. What does the ratio of the

y-coordinate to the x-coordinate

for each pair of points on the

graph represent?

d. Use the graph to find the bear’s

average heart rate when it is

active and when it is hibernating.

e. When is the bear’s heart rate greater, when it is active or when it is

hibernating? How can you tell this from the graph?

32. TIRES At Tire Depot, a pair of new tires sells for $216. The manager’s
    special advertises the same tires selling at a rate of $380 for 4 tires. How
    much do you save per tire if you purchase the manager’s special?


33. MATH IN THE MEDIA Find examples of grocery item prices in a newspaper,
    on television, or on the Internet. Compare unit prices of two different
    brands of the same item. Explain which item is the better buy.

Real-World Link

The record for the

Boston Marathon’s

wheelchair division is

1 hour, 18 minutes,

and 27 seconds.

RR

T

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