Population of a town is $5 \times 10^{4}$ and grows by a factor of 2 every 10 years. The population after 30…

Population of a town is $5 \times 10^{4}$ and grows by a factor of 2 every 10 years. The population after 30 years is
  1. $4 \times 10^{5}$
  2. $1.5 \times 10^{5}$
  3. $5 \times 10^{12}$
  4. $5 \times 10^{7}$

Solution

30 years $= 3$ doublings, factor $= 2^{3} = 8$. New population $= 5 \times 10^{4} \times 8 = 4 \times 10^{5}$.

Asked in: NSO

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