Three years ago, the population of a town was 50000. If the annual increase during three successive years be at the rate of 5%, 4% and 3% respectively, what is its present population?
Population of a town, P = 50000
Interest rate for 1st year, p = 5%
Interest rate for 2nd year, q = 4%
Interest rate for 3rd year, r = 3%
Time, n = 3 years
Now,
Present population = P × (1 + p/100) × (1 + q/100) × (1 + r/100)
= 50000 × (1 + 5/100) × (1 + 4/100) × (1 + 3/100)
= 50000 × (1 + 1/20) × (1 + 1/25) × (1 + 3/100)
= 50000 × 21/20 × 26/25 × 103/100
= 50 × 21/2 × 26/25 × 103
= 1 × 21 × 26 × 103
= 56238
∴ Present population of a town is 56238.