Question

7th maths 8.2 exercise please solve
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Answer 1

Answer :

Ex 8.2 Class 7 Maths Question 2.

Convert the given decimal fractions to per cents:

(а) 0.65

(b) 2.1

(c) 0.02

(d) 12.35

Solution:

(a) 0.65 = 0.65×100100 = 0.65 × 100% = 65%

(b) 2.1 = 2.1×100100 = 2.1 ×100% = 210%

(c) 0.02 = 0.02×100100 = 0.02 × 100% = 2%

(d) 12.35 = 12.35×100100 = 12.35 × 100% = 1235%

Ex 8.2 Class 7 Maths Question 3.

Estimate what part of the figures is coloured and hence find the per cent which is coloured.

Solution:

(i) Fraction of coloured part = 14

∴ Percentage of coloured parts 100

ii) Fraction of coloured part = 36

∴ Percentage of coloured parts

(iii) Fraction of coloured part = 68

∴ Percentage of coloured parts

Ex 8.2 Class 7 Maths Question 4.

Find:

(a) 15% of 250

(b) 1% of 1 hour

(c) 20% of ₹ 2500

(d) 75% of 1 kg

Solution:

We have,

= (15/100) × 250

= (15/10) × 25

= (15/2) × 5

= (75/2)

= 37.5

(b) 1% of 1 hour

Solution:-

We know that, 1 hour = 60 minutes

Then,

1% of 60 minutes

1 minute = 60 seconds

60 minutes = 60 × 60 = 3600 seconds

Now,

1% of 3600 seconds

= (1/100) × 3600

= 1 × 36

= 36 seconds

(c) 20% of ₹ 2500

Solution:-

We have,

= (20/100) × 2500

= 20 × 25

= ₹ 500

(d) 75% of 1 kg

Solution:-

We know that, 1 kg = 1000 g

Then,

75% of 1000 g

= (75/100) × 1000

= 75 × 10

= 750 g

Answer 2

Answer:

1

a. 65%

b. 210%

c. 2%

d. 1235%

2

a. 25%

b. 60%

c. 37.5%

3

a. 37.5

b. 0.01 hour, 3/5 min, 36 sec.

c. Rs.500

d. 0.75kg, 750g

4

a. 12000

b. Rs.9000

c. 1250 Km

d. 20 min

e. 500liters

5

a. deci: 0.25, frac: 1/4

b. deci: 1.5, frac: 3/2

c. deci: 0.2, frac: 1/5

d. deci: 0.05, frac: 1/20