Question

The population of a village decreases at the rate of 20% per annum. if its population 2 years ago was 10,000. what is its present population?

Answer 1

Heya ☺

Given that

Population of a village 3 years ago = 10,000

Rate of growth = 20 % p.a.

Time period = 2 years

Solution

Present population = P(1-R/100)^n

= 10,000(1-20/100)^2

= 10,000(100-20/100)^2

= 10,000(80/100)^2

= 10,000(4/5)^2

= 10,000 × 16/25

= 6,400


Thanks

Answer 2

Answer:

Given

population 2 years ago(P) = 10,000

Rate(R) =20% per annum

We know that present population is given by the formula

Present population = P(1-R/100) ^2

=10000(1- 20/100) ^2

=10000(80/100) ^2

=10000x(4/5) ^2

=10000x(16/25)

=6400

Hence the present population is 6400