Question

In 2004, sixty percent of population in Delhi and Mumbai were male. Given that the population of females increases at the rate of 15 percent per annum and that of males at the rate of 20 percent per annum, what will be the approximate percentage growth of population between 2004 and 2011 in Delhi and Mumbai?

• A. 150%
• B. 155%
• C. 221%
• D. 171%

Answer 1

The correct option is C

221%

Let total population of Delhi and Mumbai in 2004 = 100
Number of men in Delhi and Mumbai = 60
Therefore number of males in 2011 = 60 $\times$ (1.2)${}^7$ = 60 $\times$ 3.583 $\approx$215
Therefore number of females in 2011= 40 $\times$ (1.15)${}^7$ = 40 $\times$ 2.66 $\approx$106
Therefore total population of Delhi and Mumbai in 2011 = 321

% growth of population = $\frac{(321-100)}{100}$ $\times$ 100 $\approx$ 221%.