1. The world population growth rate at a certain reference year was 3.5%. Assuming exponential growth (घातांकी बढ़त, तेजी से विकास होने)of population, after how many years, the population of the world would have increased by a factor 16 ?
(A) ~ 80 years
(B) ~ 40 years
(C) ~ 160 years
(D) ~ 320 years

please tell me answer of this question in details way


The answer is A) ~80 years
how u solved it please explain it to me
tell me the formulla u used
ain't this from UGC test paper?