Question

the population of a city was120000in the year 2013.during next year it increased by 6percent but due to an epidemic it decreased by 5percent in the following year . what was its present population in the year 2015

Answer 1

population on 2015=120000×106/100×95/100

=12×106×95

=120840

The population in 2015 is increased by 840

percentage=100×840/120000

=0.7%

so the population increase by 0.7%

Answer 2

Answer:120840

Solution:

Population in 2013 =120000

It increased at the rate of 6%

Population in 2014 = P(1+ R/100)n

=120000 (1 +6/100)1

=120000 (53 /50 )

= 127200

Therefore,Population in 2014 =127200

It decreased at the rate of 5%

Population in 2015 =P(1- R/100)n

= 127200 (1-5/100)1

=127200 (19/20)

=120840

Hence, population in 2015 was 120840.

Hope this answer would be better.