Last year, the population of a town was x and if it increases at the same rate, next year it will be y. the present population of the town is
A. $$\frac{{x + y}}{2}$$
B. $$\frac{{y - x}}{2}$$
C. $$\frac{{2xy}}{{x + y}}$$
D. $$\sqrt {xy} $$
Answer: Option D

మణికుమార్ బండారు : Population always grow in compoundly. Ex- 100*10% = 10 in next year population = 100+ 10 so increse 110*10%= 11. in next year population 110 + 11 = 121 .......
I cannot understand it. Anyone can explain??
in the above formula why we using the compound interest formula