7th Maths : Term 3 Unit 2 : Percentage and Simple Interest: Converting Fraction to Percentage, Converting percentage as fraction : Exercise 2.1 : Text Book Back Exercises Questions with Answers, Solution

**Exercise
2.1**

**1.
In each of the following grid, find the number of coloured squares and express it
as a fraction, decimal and percentage.**

**Solution: **

**(i) **Number of coloured square = 58

Total number of squares = 100

∴ Fraction : 58 / 100

Decimal : 0.58

Percentage : 58%

**(ii)** Number of coloured square = 53

Total number of squares = 100

∴ Fraction : 53 / 100

Decimal : 0.53

Percentage : 53%

**(iii) **Number of coloured square = 25

Total number of squares = 50

∴ Fraction : 25 / 50

Decimal : 25/50 × 2/2 = 50 / 100 = 0.50

Percentage : 25/50 × 100/100 = 25/50 × 100 % = 50%

** (iv)** Number of coloured
square = 17

Total number of squares = 25

∴ Fraction : 17/25

Decimal : 17/25 × 4/4 = 68 / 100 = 0.68

Percentage : 17/25 × 100/100 = 17 / 25 × 100% = 68%

**(v)** Number of coloured square = 15

Total number of squares = 30

∴ Fraction : 15 / 30

Decimal : 15/30 = 1/2 × 50/50
= 50/100 = 0.50

Percentage : 15/30 = 15/30 × 100/100 = 15/30 × 100% = 50%

** **

**2.
A picture of chess board is given. (i) Find the percentage of the white coloured
squares. (ii) Find the percentage of grey coloured squares. (iii) Find the percentage
of the squares that have the pieces and (iv) The squares that do not have the pieces.**

**Solution: **

**(i)** Total number of squares in the chess board = 64

Number of white coloured squares = 32

Percentage = ( 32/64 ) × (100/100)

= 32/64 × 100% = 50%

**(ii)** Grey coloured squares = 64

Percentage = 32/64 × 100/100 = 32/64 × 100% = 50%

**(iii)** Number of squares having pieces = 20

Total number of squares = 64

Percentage = 20/64 × 100/100
= 20/64 × 100% = 125% / 4 = 31 (1/4)%

**(iv)** Number of squares do not have pieces = 44

Percentage = 44/64 × 100/100
= ~~44~~ / 64 = 100% =

= 275% / 4 = 68 (3/4) %

** **

**3.
A picture of dart board is given. Find the percentage of white coloured portion
and black coloured portion.**

**Solution: **

Total sector = 20

White coloured sector = 10

Black coloured sector = 10

Percentage of white : 10/20 × 100/100

Decimal : 10/20 × 100% = 50%

Percentage of black colour : 10/20 × 100/100

Decimal : 10/20 × 100% = 50%

** **

**4.
Write each of the following fraction as percentage.**

**(i)
36/50 (ii) 81/30 (iii) 42/56 (iv) 2 (1/4) (v) 1 (3/5)**

**Solution: **

**(i)** 36/50 = (36/50 ) × 100/100 = 36/50 × 100% = 72%

**(ii)** 81/30 = ( 81/30) × 100/100 = 81/30 × 100% = 270%

**(iii)** 42/56 =( 42/56) × 100/100 = 42/56 × 100% = 21/28 × 100% = 75%

**(iv)** 2 (1/4 ) = 9/4 = 9/4 × 100/100 = (9/4) × 100% = 225%

**(v)** 1 (3/5) = 8/5 = 8/5 × 100/100 = 8/5 × 100% = 160%

** **

**5.
Anbu scored 436 marks out of 500 in his exams. What was the percentage he scored?**

**Solution:**

Total marks = 500;

Anbu's Score = 436

Percentage = (436/500) × 100/100 = ( 436/500 ) × 100% = 87.2%

Anbu's Score = 87.2%

** **

**6.
Write each of the following percentage as fraction.**

**(i)
21% (ii) 93.1% (iii) 151% ( iv) 65% (v) 0.64%**

**Solution: **

**(i)** 21% = 21/100

**(ii)** 93.1% = 93.1/100 = [93.1 × 10 ] / [100 × 10] = 931/1000

**(iii)** 151% = 151/100

**(iv)** 65% = 65/100 = 13/20

**(v)** 0.64% = [0.64 × 100] / [100 × 100] = 64/10000 = 4/625

** **

**7.
Iniyan bought 5 dozen eggs. Out of that 5 dozen eggs, 10 eggs are rotten. Express
the number of good eggs as percentage.**

**Solution:**

1 dozen eggs = 12

5 dozen = 5 × 12

Total eggs = 60 eggs

Rotten eggs = 10

Good eggs = 60 – 10 = 50

Fraction of good eggs = 50/60

Percentage of good eggs = ( 50/60) × 100/100 = (50/60) × 100% =
83.33%

Percentage of good eggs = 83. 33%

** **

**8.
In an election, Candidate X secured 48% of votes. What fraction will represent his
votes?**

**Solution: **

Percentage of votes × secured = 48% = 48/100

Fraction of votes × secured = 12/25

** **

**9.
Ranjith’s total income was ₹ 7,500. He saved 25% of his total income. Find the amount
saved by him.**

**Solution:**

Total income of Ranjith = ₹ 7500

His savings = 25% of 7500 = 25/100 of 7500 = (25/100 )x 7500 = ₹
1,875

∴ Amount saved by Ranjith = ₹1,875

** **

__Objective type Questions__

**10.
Thendral saved one fourth of her salary. Her savings percentage is**

(i) 3/4 %

(ii) 1/4 %

(iii) 25%

(iv) 1%

**Solution: **1/4 × 100/100 = 1/4 × 100% = 25%

**[Answer:
(iii) 25%]**

**11.
Kavin scored 15 out of 25 in a test. The
percentage of his marks is **

(i) 60%

(ii) 15%

(iii) 25%

(iv) 15/25

**Solution: **15/25 × 100/100 = 15/25 × 100% = 60%

**[ Answer:
(i) 60% ]**

**12.
0.07% is 7 **

(i) 7/10

(ii) 7/100

(iii) 7/1000

(iv) 7/10,000

**Solution: **0.07% = 0.07 / 100 = ( [7/100] / 100 ) = 7 / (100 × 100) = 7 /
10,000

** [Answer: (iv) 7 / 10,000]**

__ANSWER:__

**Exercise 2.1 **

1. (i) 58/100, 0.58,
58% (ii) 53/100, 0.53, 53% (iii) 25/50 , 0.50, 50% (iv) 17/25 ,0.68, 68% (v) 15/30 , 0.50, 50%

2. (i) 50% (ii) 50%
(iii) 31 (4/16)% (iv) 68 (12/16)%

3. White colour– 50%
; Black colour – 50 %

4. (i) 72% (ii) 270%
(iii) 75% (iv) 225% (v) 160%

5. 87.2 %

6. (i) 21/100 (ii) 931/1000
(iii) 151/100 (iv) 13/20 (v) 4/625

7. 83.33%

8. 12/25

9. ₹ 1, 875

**Objective type questions **

10.(iii) 25%

11. (i) 60%

12. (iv) 7/10,000

Tags : Questions with Answers, Solution | Term 3 Chapter 2 | 7th Maths , 7th Maths : Term 3 Unit 2 : Percentage and Simple Interest

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7th Maths : Term 3 Unit 2 : Percentage and Simple Interest : Exercise 2.1 (Converting Fraction to Percentage, percentage as fraction) | Questions with Answers, Solution | Term 3 Chapter 2 | 7th Maths

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