Example Question - growth rate calculation

Growth Rate Calculation of City's Population

Given: The population increases by 10% each year for 2 years. Let the population in 2015 be \( P \). Thus, the population in 2016 \( = P \times (1 + \frac{10}{100}) = 1.10P \). And the population in 2017 \( = 1.10P \times (1 + \frac{10}{100}) = 1.10P \times 1.10 = 1.21P \). Let \( k \) be the factor by which the population has increased from 2015 to 2017. Therefore we have \( kP = 1.21P \). Solving for \( k \): \( k = \frac{1.21P}{P} = 1.21 \). Hence, the value of \( k \) is 1.21. The correct answer is \( D \).