Page 132 - Start Up Mathematics_7

Example 13: A school cricket team played 16 matches in one season. It won 75% of them. How
many matches did it lose?

Solution: Total number of matches played = 16
Percentage of matches won = 75%
Percentage of matches lost = 100% – 75% = 25%
25 1
Matches lost = 25% of 16 = × 16 = × 16 = 4
100 4
EXERCISE 8.1

1. Find the ratio of:

(a) 3 m to 30 cm (b) 1 day to 4 hours (c) 10 kg to 500 g (d) ` 50 to 25 paise
2. Express the following ratios in the simplest form:

(a) 1 hour 15 minutes : 30 minutes (b) 2 kg 250 g : 5 kg
(c) 2 m 30 cm : 10 cm (d) 75 paise : 2 rupees 25 paise

3. Convert the given fractions to percentages:
3 3 7 11
(a) 4 (b) 25 (c) 40 (d) 16

4. Express each of the following as a ratio:
(a) 33% (b) 24% (c) 15% (d) 62.5%

5. Express each of the following as percentages:
(a) 0.01 (b) 0.43 (c) 0.005 (d) 0.93
6. If 30% of p is 9, find the value of p.

7. What percentage of 42 is 14?
8. What percentage of 2 hours is 36 minutes?

9. Find the sum of 15% of 75 and 5% of 75. Is it equal to 20% of 75?
10. On an average 3 people can eat 1,200 g of rice. How much rice will be needed for
36 people?
11. The number of students in school A is 3,600 and in school B is 2,400. The area of school
A is 1,800 sq. m and the area of school B is 800 sq. m.

(a) How many students are there per sq. m. in both the schools?
(b) Which school is thickly populated?

12. The salary bill of company A having 60 employees is ` 9,00,000 per month and the salary
bill of company B having 75 employees is ` 12,00,000 per month.
(a) Find the average salary of the employees in both the companies.
(b) Which company is paying better average salary?

Converting ratio into percentage

To convert a ratio into a percentage, first change the ratio into fraction, then multiply the fraction
by 100 and finally put ‘%’ sign.

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