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  1. Chapter 8 Class 8 Comparing Quantities
  2. Serial order wise
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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 โˆ’ 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 โˆด Estimated Population = 23,153

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Davneet Singh
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.