Question

If population of a city increases 5% annually and its current population is 800000. What will be the population of this city after 3 year?
1. 92000
2. 926100
3. 920000
4. 880000

Answer 1

Correct Answer - Option 2 : 926100

Given:

Current population is 800000

Growth percentage is 5%

Time is 3 years

Formula used:

A = P(1 + r/100)^t

Here, A = Total population after 3 year

P = Current population

r = Growth percentage

t = Time

Calculation:

A = 800000(1 + 5/100)³

⇒ A = 800000(1 + 1/20)³

⇒ A = 800000(21/20)³

⇒ A = (800000 × 21 × 21 × 21)/(20 × 20 × 20)

⇒ A = 100 × 9261

⇒ A = 926100

∴ Population of town after 3 year is 926100.

The population growth rate is always in compound rate instead of simple rate.