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We might have come across the term percentage in our lives.
The percentage is indicated by the symbol %. • The rate of growth of an economy is 12% per year. • He has scored 98% marks in his maths paper. • The price of a computer has gone up by 15%. • The growth in the population of a country is 21% over previous year. • 54% of the students of a university is boys. These are the news which we come across quite often in our lives. Could you guess what the term percentage means? Yes. You are right. Percentage mean per 100. The term cent means 100. Percentage means per cent which implies per 100. Example : 1 The shop-owner sells his calculator at the rate of $120 per piece. He wants to increase the selling price of the calculator by 10% per piece. What will be the new selling price of a calculator? The original selling price of a calculator = $120 10% of 120 = (10/100) x 120 = (10 x 120) / 100 = 1200/100 = 12 The selling price of a calculator will go up by $12. The new selling price of a calculator = $120 + $12 = $132. The new selling price of a calculator = $132. Example : 2 There are 210 students studying in a school. 60% of them are boys. How many boys are there is the school? The remaining students are girls. How many students are girls? The total number of students = 210 60% of them are boys. 60% of 210 = (60/100) x 210 = (60 x 210) / 100 = 12600/100 = 126 So, the number of boys = 126 The remaining students are girls. The number of girls = 210 – 126 = 84 The number of girls = 84 Example : 3 The length and the breadth of a rectangular plot are 20 metres and 12 metres respectively. 75% of its area is allotted for meadow. What is the area of the plot allotted for meadow? The length of the rectangular plot = 20 metres The breadth of the rectangular plot = 12 metres The area of the rectangular plot = 20 x 12 = 240 square metres 75% of its area is allotted for meadow. 75% of 240 = = (75/100) x 240 = (75 x 240) / 100 = 18000 / 100 = 180 75% of 240 = 180 The area of the plot allotted for meadow = 180 square metres Example : 4 The salary of John is $2000 per month. He saves 12% of this per month. How much does he save per month? John’s salary = $2000 per month He saves 12% of this per month. 12% of 2000 = = (12/100) x 2000 = (12 x 2000) / 100 = 24000 / 100 = 240 12% of 2000 = 240 He saves $240 per month. Percentage : Exercise - 1
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