Post on 19-Mar-2017
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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?
43
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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? -