Selina Solutions Concise Maths Class 7 Chapter 8 Percent and Percentage Exercise 8A covers major topics like basic concept and the method of expressing a given statement as percent. In a subject like Mathematics, the students should first understand the important concepts, as per ICSE syllabus. The solutions contain important formulas and shortcut tricks, which are used in solving the exercise wise problems. After solving the textbook problems, students can cross check their answers with Selina Solutions Concise Maths Class 7 Chapter 8 Percent and Percentage Exercise 8A PDF, using the links provided below.
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Access Selina Solutions Concise Maths Class 7 Chapter 8: Percent and Percentage Exercise 8A
1. Express each of the following as percent:
(i) 3/4
(ii) 2/3
(iii) 0.025
(iv) 0.125
Solution:
(i) 3/4
We can write it as
= 3/4 × 100
So we get
= 75%
(ii) 2/3
We can write it as
= 2/3 × 100
So we get
= 200/3
= 66 2/3 %
(iii) 0.025
We can write it as
= 25/1000 × 100
So we get
= 25/10%
= 2.5%
(iv) 0.125
We can write it as
= 125/1000 × 100
So we get
= 125/10
= 12.5%
2. Express the following percentages as fractions and as decimal numbers:
(i) 7 ½ %
(ii) 2.50 %
(iii) 0.02 %
(iv) 175 %
Solution:
(i) 7 ½ %
We can write it as
= 15/ (2 × 100)
So we get
= 15/200
= 0.075
(ii) 2.50 %
We can write it as
= 250/ (100 × 100)
So we get
= 250/10000
= 0.0250
= 0.025
(iii) 0.02 %
We can write it as
= 0.02/100
So we get
= 2/ (100 × 100)
= 2/10000
By further calculation
= 0.0002
(iv) 175 %
We can write it as
= 175/100
So we get
= 7/4
= 1.75
3. What percent is:
(i) 16 hours of 2 days?
(ii) 40 paisa of ₹ 2?
(iii) 25 cm of 4 metres?
(iv) 600 gm of 5 kg?
Solution:
(i) 16 hours of 2 days
We can write it as
= 16/ (2 × 24)
So we get
= 16/48 × 100%
Here
= 100/3%
= 33 1/3 %
(ii) 40 paisa of ₹ 2
We can write it as
= 40/ (2 × 100)
So we get
= 40/200 × 100%
Here
= 20%
(iii) 25 cm of 4 metres
We can write it as
= 25/ (4 × 100)
So we get
= 1/16 × 100%
Here
= 25/4%
= 6 ¼%
(iv) 600 gm of 5 kg
We can write it as
= 600/ (5 × 1000) × 100%
So we get
= 12%
4. Find the value of:
(i) 5% of ₹ 350
(ii) 10% of ₹ 400.40
(iii) 1% of ₹ 500
(iv) 12 ½ % of 80 kg
(v) 5/8 % of ₹ 600
(vi) 33 1/3 % of 27 m
Solution:
(i) 5% of ₹ 350
We can write it as
= 350 × 5/100
So we get
= 35/2
= ₹ 17.50
(ii) 10% of ₹ 400.40
We can write it as
= 400.40 × 10/100
So we get
= ₹ 40.04
(iii) 1% of ₹ 500
We can write it as
= 500 × 1/100
So we get
= ₹ 5
(iv) 12 ½ % of 80 kg
We can write it as
= 80 × 25/ (2 × 100)
So we get
= 10 kg
(v) 5/8 % of ₹ 600
We can write it as
= 600 × 5/ (8 × 100)
So we get
= ₹ 15/4
= ₹ 3.75
(vi) 33 1/3 % of 27 m
We can write it as
= 27 × 100/ (3 × 100)
So we get
= 9 m
5. In a class of 60 children, 30% are girls. How many boys are there?
Solution:
No. of children = 60
Percentage of girls = 30%
So total number of girls = 30% of 60
We can write it as
= 60 × 30/100
= 18
Number of boys = 60 – 18 = 42
6. In an election, two candidates A and B contested. A got 60% of the votes. The total votes polled were 8000. How many votes did each get?
Solution:
Total votes polled = 8000
A got 60% of the votes
Number of votes A got = 60% of 8000
We can write it as
= 8000 × 60/100
= 4800
Number of votes B got = 8000 – 4800 = 3200
7. A person saves 12% of his salary every month. If his salary is ₹ 2,500, find his expenditure.
Solution:
Salary = ₹ 2,500
Saving in every month salary = 12% of salary
So the total savings = 12% of ₹ 2,500
We can write it as
= 2500 × 12/100
= ₹ 300
Total expenditure = 2500 – 300 = ₹ 2200
8. Seeta got 75% marks out of a total of 800. How many marks did she lose?
Solution:
Total marks = 800
Marks scored by Seeta = 75% of total marks
Total marks scored by Seeta = 75% of 800
We can write it as
= 800 × 75/100
= 600
So the marks lost by Seeta = 800 – 600 = 200
9. A shop worth ₹ 25, 000 was insured for 95% of its value. How much would the owner get in case of any mishappening?
Solution:
Worth of shop = ₹ 25, 000
Amount insured = 95% of its values
We can write it as
= 95% of ₹ 25, 000
So we get
= ₹ 25, 000 × 95/100
= ₹ 23, 750
10. A class has 30 boys and 25 girls. What is the percentage of boys in the class?
Solution:
Number of boys = 30
Number of girls = 25
So the total number of children = 30 + 25 = 55
So the percentage of boys in the class = 30/55 × 100
We get
= 600/11
= 54 6/11 %
11. Express:
(i) 3 2/5 as percent
(ii) 0.0075 as percent
(iii) 3: 20 as percent
(iv) 60 cm as percent of 1 m 25 cm
(v) 9 hours as percent of 4 days.
Solution:
(i) 3 2/5 as percent
We can write it as
3 2/5 = (3 × 5 + 2)/ 5 = 17/5
By converting 17/5 as a percent
= 17/5 × 100
= 340%
(ii) 0.0075 as percent
We can write it as
0.0075 × 100 = 0.75%
(iii) 3: 20 as percent
We can write it as
= 3/20 × 100
So we get
= 15%
(iv) 60 cm as percent of 1 m 25 cm
We can write it as
60 cm as percent of (1 × 100 + 25) cm
We know that 1m = 100 cm
So we get
= 60/125 × 100
By further calculation
= 12 × 4
= 48%
(v) 9 hours as percent of 4 days
We know that 1 day = 24 hours
So 4 days = 4 × 24 = 96 hours
We can write it as
= 9/96 × 100
= 75/8%
= 9 3/8%
12. (i) Find 2% of 2 hours 30 min.
(ii) What percent of 12 kg is 725 gm?
Solution:
(i) 2% of 2 hours 30 min
We know that
1 hour = 60 minutes
So we get
2 hours 30 min = 2 × 60 + 30
= 120 + 30
= 150 min
We can write it as
= 150 × 2/100
So we get
= 30/10
= 3 minutes
(ii) 12 kg is 725 gm
We know that
1 kg = 1000 gm
So we get
12 kg = 12 × 1000 = 12000 gm
We can write it as
= 725/12000 × 100
So we get
= 725/120
= 145/24%
= 6 1/24%
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