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Example 3: Out of 35 students in a class, 21 are girls. What is the percentage of boys and girls in
the class?
Solution: In class there are 21 girls out of 35 students.
21 300
Therefore, the required percentage of the girls in the class = 35 × 100 % = 5 % = 60%
Number of boys in the class = 35 – 21 = 14
The percentage of the boys in the class Quick Check
14 200 Out of 150 voters, 60 of them
= 35 × 100 % = 5 % = 40% voted to A and 90 of them voted
to B. What per cent voted to B?
Thus, there are 40% boys and 60% girls in the class.
Converting Decimals into Percentages
To convert a decimal number into a percentage, multiply the given decimal number by 100 and
put the symbol %. Alternatively shift the decimal point two places to the right and put % sign to
convert the decimal into percentage.
Example 4: Convert each of the following decimals into percentage.
(a) 4.5 (b) 10.4 Alternative Method:
(c) 0.36 (d) 0.007 (a) 4.5 = 45 = 45 × 100 % = 450%
10 10
Solution: (a) 4.5 = (4.5 × 100) % = 450 % 104 104
(b) 10.4 = = × 100 % = 1040%
10
(b) 10.4 = (10.4 × 100) % = 1040 % 36 10
36
(c) 0.36 = = × 100 % = 36%
(c) 0.36 = (0.36 × 100) % = 36% 100 100
7 7
(d) 0.007 =(0.007 × 100) % = 0.7 % (d) 0.007 = 1000 = 1000 × 100 % = 0.7%
Converting Percentages into Fractions
To convert the given percentage into a fraction, divide the percentage by 100 and remove the symbol
%. And simplify if required.
Example 5: Convert each of the following percentages into fractions.
(a) 55% (b) 43% (c) 62.5% (d) 124%
Solution: We have,
55 11 43
(a) 55% = = (b) 43% =
100 20 100
62 5 625 625 5 5 1
.
(c) 62.5% = 100 = 100 10 = 1000 = 40 = 8 Think and Answer
×
124 31 40 Convert 125.6% to a
(d) 124% = = fraction and simplify it.
100 25
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