In the first year the population of a town decreased by 5% due to the Corona virus first wave. In the next year it decreased again by 5% due to the second wave and in the third year it increased by 5%. At the end of the third year the population was 9,47,625. What was the population at the beginning of the first year?
10,00,000
This problem involves calculating the original population of a town based on percentage changes over three consecutive years. We are told the population experienced specific changes linked to the Corona virus waves.
We need to reverse the percentage changes to find the initial population. Let's denote the initial population as \(P_0\).
We will calculate the population year by year, setting up an equation based on the final population.
The population decreased by 5%. This means the remaining population is \(100\% - 5\% = 95\%\) of the population at the start of the year. Population after Year 1, \(P_1 = P_0 \times (1 - \frac{5}{100})\) \(P_1 = P_0 \times (1 - 0.05)\) \(P_1 = P_0 \times 0.95\)
The population again decreased by 5% from the end of Year 1 population (\(P_1\)). Population after Year 2, \(P_2 = P_1 \times (1 - \frac{5}{100})\) \(P_2 = P_1 \times 0.95\) Substituting the value of \(P_1\): \(P_2 = (P_0 \times 0.95) \times 0.95\) \(P_2 = P_0 \times (0.95)^2\) \(P_2 = P_0 \times 0.9025\)
The population increased by 5% from the end of Year 2 population (\(P_2\)). Population after Year 3, \(P_3 = P_2 \times (1 + \frac{5}{100})\) \(P_3 = P_2 \times (1 + 0.05)\) \(P_3 = P_2 \times 1.05\) Substituting the value of \(P_2\): \(P_3 = (P_0 \times 0.9025) \times 1.05\) \(P_3 = P_0 \times 0.947625\)
We are given that the population at the end of the third year (\(P_3\)) is 9,47,625. So, \(P_0 \times 0.947625 = 9,47,625\)
To find the initial population, we need to isolate \(P_0\). \(P_0 = \frac{9,47,625}{0.947625}\) To simplify the division, we can write 0.947625 as a fraction: \(0.947625 = \frac{947625}{1000000}\) \(P_0 = \frac{9,47,625}{\frac{947625}{1000000}}\) \(P_0 = 9,47,625 \times \frac{1000000}{947625}\) \(P_0 = 1,000,000\)
After performing the calculations step-by-step, we found that the population at the beginning of the first year was 1,000,000. This is the original number of people in the town before the described changes occurred.
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