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FRACTIONS, DECIMALS, AND PERCENTAGES

Dr. Farhana Shaheen

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OBJECTIVES Change each fraction to a decimal fraction,

and then to a percent.

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CHANGING DECIMALS TO FRACTIONS

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QUES: WRITE THE FRACTION OR MIXED FRACTION AS A DECIMAL.

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SOLUTION:

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CHANGE EACH FRACTION TO A DECIMAL FRACTION, AND THEN TO A PERCENT Rules:

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EXAMPLE # 1 Change each fraction to a decimal fraction,

and then to a percent.

Solution:52

26.0)d123

1)c2545

)b2013

)a

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Solution:

%%4.26100x264.0:Percent

264.052

26.0:fractionDecimal)d

%125100x25.1:Percent

25.11231:fractionDecimal)c

%180100x8.1:Percent

8.12545:fractionDecimal)b

%65100x65.0:Percent

65.02013

:fractionDecimal)a

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EXAMPLE # 2 Change each to a common or mixed fraction,

and then to a decimal fraction.

Solution:

%5226.0)d%

123108)c%

2545)b%

2013)a

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SOLUTION:

00264.0100264.0fractionDecimal

1250033

100000264100264.0100

5226.0:fractionCommon)d

0825.112001299:fractionDecimal

400331

12001299100

123108:fractionMixed)c

180.05009

:fractionDecimal

5009

250045

1002545

:fractionCommon)b

0065.0200013:fractionDecimal

200013

1002013

:fractionCommon)a

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EXERCISE: Q.1. Change each to a percent. a) 0.07 b) 0.245 c) 5

d) e) f) 2

g) 1.02

3213

916

53

43

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Q.2. Change each to a decimal fraction.

a) 17% b) 5.6% c) 0.058%

d) e) f)

g) 0.08 %

%5213

%2112 %

517

43

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Q.3. Change each to a common fraction or a mixed fraction.

a) 48% b) 327.5% c) 0.055%

d) e) f)

g) 155 %

%5117

%416

53

%5

27

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APPLICATIONS OF PERCENTS

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APPLICATIONS OF PERCENTS

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SOLUTIONS:

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SKILLSWISE

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SOLUTIONS:

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PERCENTAGE RULE:

IF A% of B is C then: Example: 30% of 70

AB = 100C

Note: “Per cent”(%) means “out of 100” i.e. A/100 “Of” means “Multiply” “is” put =

CBA

100 217010030

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EXAMPLE # 3

Using RULE: IF A% of B is C then: AB = 100C Note: “Per cent”(%) means “out of 100” “Of” means “Multiply” Solution:

?25040)?35%20)?500%40)

ofpercentwhatiscisnumberwhatofbofisnumberWhata

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SOLUTION:

%16250

40100A40100A250)c

17520

35100B 35100B20)b

200100

50040CC10050040)a

?250ofpercentwhatis40)c?35isnummberwhatof%20)b?500of%40isnumberWhat)a

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EXAMPLE # 4 (a) A football team won 16 of the 25 games

it played. What percent of its games it has won?

Solution: RULE: IF A% of B is C then: AB =

100C

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EXAMPLE # 4 (b) 76% of Math students passed. If there

were 350 students, how many of them did pass?

Solution: RULE: IF A% of B is C then: AB =

100C

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EXAMPLE # 4 (c) A laptop is sold for SR2550 at 15%

discount. What is the original price of the laptop?

Solution: RULE: IF A% of B is C then: AB =

100C

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Solution: RULE: IF A% of B is C then: AB =

100C

.3000SR85

2550100B:priceOriginal

2550100B85.,e.i2550isBof%85discount%15)c

passedstudents266100

35076CC10035076)b

%6425

16100A16100A25)a

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QUESTION FOR YOU-

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QUESTION FOR YOU-

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EXERCISE: 1. What percent of 60 is 340?

2. 27 % of what number is 111?

3. How much is 150% of 6?

4. SR 127.50 is 0.85% of what salary?

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5. What percent of a meter is 3 km?

6. % of a foot equals how many inches?31

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7. The sales tax was 12%. What was the total purchase on which SR 420 were paid as sales tax?

8. The sales tax on a sale of SR 42625 is SR5115. What is the percent tax rate?

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9. Ali has 20 assignment questions. He has solved 60% of them. How many questions are left?

10. The salary of a technician increased from SR 7650 to SR 8262. What was the percent increase?

11. The gold price increased by 6%. If a gold-ring now costs SR 265, how much did it cost last year? -