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# proportion

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1 If you drive 151.7miles on 8.2 gallons of gas, what is the simplified ratio of miles to gallons?

2 Solve the proportion for the item represented by a letter:

3 Solve the proportion for the item represented by a letter:

4 If two quarts of paint are needed for 75 ft of fence, how many quarts are needed for 900 ft of fence?

5 Estimate the percentages:

a. 75% of 1,058 b. 75% of 94

6 Write the sentence as a proportion, then solve to answer the question: 40% of what number is 60?

7 If the sales tax is 5.5% and purchase price is \$680, what is the amount of tax?

8 If 20 is increased to 25, what is the percent increase?

9 A certain test is worth 125 points. How many points (rounded to the nearest point) are needed to obtain a score of 75%?

10 Calculate the amount of simple interest earned: \$1,000 at 8% for 5 years

(cont.)

11 If \$34,500 is invested at 6.9% for 30 years, find the future value if the interest is compounded:
a. annually
b. semiannually
c. quarterly
d. monthly
e. daily
f. every minute (N=525,600)
g. continuously
h. simple (not compounded)

12 Find the cost of each item in 10 years, assuming an inflation rare of 5%:
b. CD, \$14.95
c. textbook, \$90.00
d. electric bill,\$105
e. phone bill, \$45
f. pair of shoes \$85
g. new suit, \$570
h. monthly rent, \$800

13 If Rita receives \$45.33 interest for a deposit earning 3% simple interest for 240 days, what is the amount of her deposit.

https://brainmass.com/math/consumer-mathematics/ratios-percents-interests-problem-solving-306907

#### Solution Preview

p.320 #10 If you drive 151.7miles on 8.2 gallons of gas, what is the simplified ratio of miles to gallons?

Ratio = 151.7/8.2 = 1517/82 = 37/2

p.320 #32 Solve the proportion for the item represented by a letter:

Solution:

Cross multiply

4N = 3 ×
4N = 3 ×
4N = 8
N = 8/4 = 2

p.320 #34 Solve the proportion for the item represented by a letter:

Which gives
5 × = 2Q

5 × = 2Q
63 = 2Q
Q = 63/2 =

p.320 #46 If two quarts of paint are needed for 75 ft of fence, how many quarts are needed for 900 ft of fence?

Let x be the number of quarts needed
Proportion will be

x/900 = 2/75
75x = 900*2
75x = 1800
x = 1800/75 = 24 quarts

p.330 #26 Estimate the percentages:

a. 75% of 1,058

Estimate 1058 t0 1000

75% of 1000 = 750