The population of a town was 3600 three years back It is 4800 right now What will be the population ...........

Explanation:

The population grew from 3600 to 4800 in 3 years.

That is a growth of 1200 on 3600 during three year span.

Therefore, the rate of growth for three years has been constant.

The rate of growth during the next three years will also be the same.

Therefore, the population will grow from 4800 by 4800*1/3 = 1600

The population three years from now will be 4800 + 1600 = 6400

Hence, option 1 is the correct answer.