Answer: A
Let the population \(n\) years ago be \(x\).
∴ According to the condition, \(x(1+\cfrac{r}{100})^n = p\)
or, \(x = \cfrac{p}{(1+\cfrac{r}{100})^n}\)
or, \(x = p(1+\cfrac{r}{100})^{-n}\)
Let the population \(n\) years ago be \(x\).
∴ According to the condition, \(x(1+\cfrac{r}{100})^n = p\)
or, \(x = \cfrac{p}{(1+\cfrac{r}{100})^n}\)
or, \(x = p(1+\cfrac{r}{100})^{-n}\)