Question

The population of a city increases each year by 4% of what it had been at the beginning
of each year. If its present population is 6760000, find :
(i) its population 2 years hence (ii) its population 2 years ago.
​

Answer 1

Answer:

It is given that

Present population = 6760000

Increase percent = 4% p.a.

(i) We know that

Population 2 years hence = P(1+r/100)

n

Substituting the values

= 6760000(1+4/100)

2

By further calculation

=6760000×26/25×26/25

=7311616

(ii) We know that A = 6760000

Population 2 years ago P=A+(1+r/100)

2

Substituting the values

= 6760000+(1+4/100)

2

By further calculation

= 6760000+(26/25)

2

=6760000×25/26×25/26

= 6250000