I am provided with an example for an Exponential mode, but I can't understand parts of it, I'd appreciate if some one could explain them a bit more.

Question:

*There are apporximately ***ten times as many red kangaroos as grey kangatoos** **<<<<< see question 2** in a certain area. If the population of grey kangaroos increases at a rate of 11% per annum while that of the red kangaroos decreases at 5% per annum, find how many years must elapse before the proportions are reversed, assuming the same rates continue to apply.
Solution

Let

= population of grey kangaroos at the start.

Therefore the number of grey kangaroos after

years =

The number of red kangaroos after

years =

**Question 1 : Why is the percentage raised to the power of ** ** (+n years later)?**
When Proportions are reversed:

**Question 2 : Why is multiplied by ** **? **