Question

the population of a city was 100000 three years ago. it increased at a rate of 5 per annum. find its population at present.

Answer 1

old population = 100000
increased percent= 5%pa
so new population=
$100000 ({ \frac{100 + 5}{100} })^{3} \\ 100000( { \frac{105}{100} })^{3} \\ 100000( { \frac{21}{20} })^{3} \\ 100000( {1.05)}^{3} \\ 100000(1.157625) \\ 115763 approx$