# Example 14 - Chapter 8 Class 8 Comparing Quantities

Last updated at Nov. 12, 2018 by Teachoo

Last updated at Nov. 12, 2018 by Teachoo

Transcript

Example 14 The population of a city was 20,000 in the year 1997. It increased at the rate of 5% p.a. Find the population at the end of the year 2000. Population of city in 1997 = 20,000 It Increases at the Rate of 5% Per Annum Here, 5% is compounded Rate So we use the formula A = P (1+๐ /100)^๐ Here, A = Population at end of 2000 P = Population in 1997 = 20,000 R = 5 % N = 2000 โ 1997 = 3 Putting Values in Formula Population at end of 2000 = 20000 (1+5/100)^3 = 20000 (1+1/20)^3 = 20000 ((20 + 1)/20)^3 = 20000 (21/20)^3 = 20000 ร (21 ร 21 ร 21)/(20 ร 20 ร 20) = (5 ร 21 ร 21 ร 21)/2 = (441 ร 21 ร 5)/2 = (441 ร 105)/2 = 46305/2 = 23152.5 Since population cannot be in decimals โด Estimated Population = 23,153

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.