Доли акций в портфеле

I own $20,000 stocks of Increases SA, and $10,000 stocks of Incrisis SA.

While Increases SA was growing by 9% per year, Incrisis SA was shrinking by 9% per year.

How many years prior (approximately) my portfolio was allocated 50-50?

Варианты ответа:

1. 2
2. 4
3. 8
4. 16
5. I will not answer this question