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Question
The annual rate of growth in population of a certain city is 8%. If its present population is 196830, what it was 3 years ago?
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Solution
Population after three years = P \[\left( 1 + \frac{R}{100} \right)^n \]
\[196, 830 = P \left( 1 + \frac{8}{100} \right)^3 \]
\[196, 830 = P \left( 1 . 08 \right)^3 \]
\[P = \frac{196, 830}{1 . 259712}\]
\[ = 156, 250\]
Thus, the population three years ago was 156, 250.
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