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TGTET Paper 1 Exam 23 Jul 2017 Paper
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Question : 111 of 150
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The present population of a city is 157464. If the population increased by 8% annually then the population of the city 3 years ago was ______
Solution:
Concept:Compound growth applied to population over time.Explanation:We are given the current population of a city and the annual growth rate. We need to find the population 3 years ago. Let's assume the population 3 years ago was .The population increases by 8% annually. This means each year the population becomes 108% of the previous year's population.So, after 1 year, the population would be .After 2 years, the population would be .After 3 years, the population would be .We are given that the present population (after 3 years of growth) is 157464.So, we can set up the equation:To find , we rearrange the formula:Let's calculate the values:Now, divide 157464 by 19683:So, the equation becomes:Therefore, the population of the city 3 years ago was 1,25,000.Answer:1,25,000
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