7th Grade Math

Multi-Part Lesson Review

Chapter Study Guide and Review 307

Proportions

Rates (Lesson 1B)

Find each unit rate.

10. $23.75 for 5 pounds


11. 810 miles in 9 days


12. SHAMPOO Which bottle of
    shampoo shown at the
    right costs the least per
    ounce?

EXAMPLE 1 Find the unit price of a

16-ounce box of pasta that is on sale for

96 cents.

16-oz box for 96 cents = __96 cents ÷^16

16 ounces ÷ 16

= _6 cents

1 ounce

The unit price is 6 cents per ounce.

Proportional and Nonproportional Relationships (Lesson 1C)

13. INTERNET An Internet company charges
    $30 a month. There is also a $30
    installation fee. Is the number of months
    you can have Internet proportional to the
    total cost? Explain.


14. WORK On Friday, Jade washed
    10 vehicles in 4 hours. The next day
    she washed 15 vehicles in 6 hours. Is
    the number of vehicles she washed
    proportional to the time it took her
    to wash them? Explain.

EXAMPLE 2 Is the amount of money

earned proportional to the number of

haircuts? Explain.

Earnings ($) 28 56 84 112

Haircuts 1234

_earningshaircuts _^28

1

, _^56

2

, _^84

3

, _^112

4

Since these ratios are all equal to 28, the

amount of money earned is proportional to

the number of haircuts.

Solve Proportions (Lesson 1D)

Solve each proportion.

15. ^3 r = ^68 16. _0.5^30 =

y

_0.25

17. 47 = 2 n 18. 5 k = ^728


18. ^2 t = 508 20. _^128 = _a 6


19. SPEED A squirrel can run 1 mile in
    5 minutes. How far can it travel in
    16 minutes?


20. WEIGHT If 3 televisions weigh
    240.6 pounds, how much do 9 of the
    same televisions weigh?

EXAMPLE 3 Solve _^9

x

= _ 184.

_x^9 = _ 184 Write the proportion.

9 · 18 = x · 4 Find the cross products.

162 = 4 x Multiply.

_^1624 = _^44 x Divide each side by 4.

40.5 = x Simplify.

Lesson 1

Bottle Price

8 oz $1.99

12 oz $2.59

16 oz $3.19

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