Converting Fractions into Decimals and Percentages. Real-life problems. Dr. Farhana Shaheen

1. FRACTIONS, DECIMALS, AND
PERCENTAGES
Dr. Farhana Shaheen
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2. OBJECTIVES
 Change each fraction to a decimal fraction, and
then to a percent.
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3. CHANGING DECIMALS TO FRACTIONS
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4. QUES: WRITE THE FRACTION OR MIXED
FRACTION AS A DECIMAL.
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5. SOLUTION:
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6. CHANGE EACH FRACTION TO A DECIMAL
FRACTION, AND THEN TO A PERCENT
 Rules:
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9. EXAMPLE # 1
 Change each fraction to a decimal fraction, and
then to a percent.

 Solution:
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5
2
26.0)d
12
3
1)c
25
45
)b
20
13
)a

10.  Solution:
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%%4.26100x264.0:Percent
264.0
5
2
26.0:fractionDecimal)d
%125100x25.1:Percent
25.1
12
3
1:fractionDecimal)c
%180100x8.1:Percent
8.1
25
45
:fractionDecimal)b
%65100x65.0:Percent
65.0
20
13
:fractionDecimal)a









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12. EXAMPLE # 2
 Change each to a common or mixed fraction, and
then to a decimal fraction.

 Solution:
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%
5
2
26.0)d%
12
3
108)c%
25
45
)b%
20
13
)a

13. SOLUTION:
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00264.0100264.0fractionDecimal
12500
33
100000
264
100264.0100
5
2
26.0:fractionCommon)d
0825.1
1200
1299
:fractionDecimal
400
33
1
1200
1299
100
12
3
108:fractionMixed)c
180.0
500
9
:fractionDecimal
500
9
2500
45
100
25
45
:fractionCommon)b
0065.0
2000
13
:fractionDecimal
2000
13
100
20
13
:fractionCommon)a









14. EXERCISE:
 Q.1. Change each to a percent.
a) 0.07 b) 0.245 c) 5
d) e) f) 2
g) 1.02
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32
13
9
16
5
3
4
3

15.  Q.2. Change each to a decimal fraction.
 a) 17% b) 5.6% c) 0.058%
 d) e) f)
 g) 0.08 %
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%
52
13
%
2
1
12 %
5
17
4
3

16.  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 %
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%
51
17
%
4
1
6
5
3
%
5
27

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18. APPLICATIONS OF PERCENTS
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19. APPLICATIONS OF PERCENTS
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20. 3/3/2017
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21. SOLUTIONS:
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22. SKILLSWISE
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23. SOLUTIONS:
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24. 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 =
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CB
A

100 2170
100
30


25. EXAMPLE # 3

 Using RULE: IF A% of B is C
 then: AB = 100C
 Note: “Per cent”(%) means “out of 100”
“Of” means “Multiply”
 Solution:
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?25040)
?35%20)
?500%40)
ofpercentwhatisc
isnumberwhatofb
ofisnumberWhata

26. SOLUTION:
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%16
250
40100
A40100A250)c
175
20
35100
B35100B20)b
200
100
50040
CC10050040)a









?250ofpercentwhatis40)c
?35isnummberwhatof%20)b
?500of%40isnumberWhat)a

27. 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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28. 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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29. 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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30.  Solution:
 RULE: IF A% of B is C then: AB = 100C
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.3000SR
85
2550100
B:priceOriginal
2550100B85.,e.i2550isBof%85discount%15)c
passedstudents266
100
35076
CC10035076)b
%64
25
16100
A16100A25)a











31. QUESTION FOR YOU-
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32. QUESTION FOR YOU-
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33. 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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4
3

34. 5. What percent of a meter is 3 km?
6. % of a foot equals how many inches?
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3
1
33

35.  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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36.  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? -
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