The population increases by 5% every year. What was the population in 1982, if in 1985 it was 1,85220?
My working:
population in 1985 = 1,85,220 rate=5% time = 3yrs ( A=P(1-R/100)^n ) therefore, population in 1982 = 185220(1 - 5/100)^3 = 158802.9975
obviously that's wrong, but where's the problem?