20 total balls:
5 are black
17 NOT yellow
12 NOT green
20-17 = 3
20-12 = 8
5 Black + 3 yellow + 8 green = 16 balls
20 total balls - 16 balls = 4 blue balls
Ewa has 4 blue balls.
Answer:
Step-by-step explanation:
1:2 can equal 1/2. Hope this helps >^_^<
At the end of the first year, the correct formula is this one:

The second year, we add r times the above amount, we get:

Iterating the process, we get the general formula of any number of years: