Answer:99 days
Step-by-step explanation:
Given
If one start with one square unit it takes 100 days
i.e. At second day it is 2 unit
third day [tex]2^2[/tex]
at n th day [tex]2^{n-1}[/tex]
at 100 day [tex]2^{99}[/tex] square unit
If we start with 2 square units it would take
[tex]2^n[/tex] for n days
[tex]2^n=2^{99}[/tex]
[tex]n=99\ days[/tex]