Class 7 Maths | Chapter 8 Comparing Quantities | Extra Questions For Practice

Answer the following:

1. Find the ratio of each of the following in simplest form:

a) Rs 5 to 50 paise
b) 18 m to 36 cm

2. Check whether the following ratios are equivalent:

a) 2:3 and 12:18
b) 4:7 and 9:12

3. Find the unknown y so that both ratios are equivalent:

a) y:8 : : 3:12
b) 24: 36:: y: 9

4. If the cost of one dozen pens are 60. Find the cost of 5 pens?

5. Divide 240 rupees between Anu and Manu in the ratio 3:5?

6. Convert the following percents into ratios and write in simplest form:

a) 15%
b) 65%

7. Convert the following ratios to percents:

a) 3:4
b) 5:8

8.30% of a number is 75. Find the number?

9. Convert the following percents to decimals:

a) 37%
b) 8%

10. Convert the following decimals to percents:

a) 0.56
b) 0.7

ANSWERS:

1. a) Rs 5 to 50 paise
We know that 100 paise = 1 rupee
Therefore, Rs 5 = 500 paise
Ratio = 500:50 = 10:1 (Divide by 50)

b) 18 m to 36 cm
We know that 100 cm = 1 m
Therefore, 18 m = 1800 cm.
Ratio = 1800:36 = 50:1 (Divide by 36)

2. a) 2:3 and 12:18
Here, 2 x 18 = 36(Extreme terms)
2 x 12 = 36 (Middle terms)
So these ratios are equivalent.

b) 4:7 and 9:12
Here, 4 x 12 = 48
7 x 9 = 63
So these ratios are not equivalent.

3. a) y:8::3:12
Since the ratios are equivalent, y x 12 = 8 x 3
y x 12 = 24
y = 24/12 = 2

b) 24:36:: y:9
Since the ratios are equivalent, 24 x 9 = 36 x y
216 = 36 x y
Y = 216/36 = 6

4. Cost of 12 pens = 60 rupees
Cost of one pen = 60/12 = 5 rupees
Cost of 5 pens = 5 x 5 = 25 rupees

5. Part of Anu = 3/8
Part of Manu = 4/8
We need to divide 240 rupees in the ratio 3:5.
Share of Anu = 240 x 3/8 = 90 rupees
Share of Manu = 240 x 5/8 = 150 rupees

6. a) 15% = 15/100 = 3/20= 3:20
b) 65% = 65/100 = 13/20 = 13:20

7. a) 3:4
¾ x 100% = 75%

b) 5:8
5/8 x 100= 62.5%

8. Let the number be y.
30% of y = 75
30/100 x y =75
30 y = 7500
Y = 7500/30 = 250

9. a) 37%
37/100 = 0.37
b) 8%
8/100 = 0.08

10. a) 0.56 =0.56 x 100% = 56%
b) 0.7 = 0.7 x 100% = 70%