The answer is 0.2
Hope this helps
5y = 4x + 20
- 4x + 5y = 20
Division and multiplication
The first 3 months are 250
6 months are 500
9 months are 1000
12 months are 2000
15 months are 4000
18 months are 8000
21 months are 16000
24 months are 32,000 which is two years