each year for the past 5 years the population of a certain country has increased at a steady rate of 2.7% per annum. the present population is 15.2 million

a) what was the population 1 year ago?

b) what was the population 5 years ago?

i dnt understand the q, has this got anything to do with compound interest field? ive slightly touched on the subject in skl, isit exponential? can i have working out please so i can understand...