Question
The population of a town increases by 10% in the first
year and by 20% in the second year. If the population at the end of two years is 39,600, find the population at the beginning of the first year.Solution
Let initial population = P After first year: P × 1.10 After second year: P × 1.10 × 1.20 = P × 1.32 P × 1.32 = 39,600 P = 39,600 / 1.32 1.32 = 132/100 ⇒ P = 39,600 × 100 / 132 = 3,960,000 / 132 132×30,000 = 3,960,000 So P = 30,000.
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