# Math Help - [probability] any help with this challenging problem?? explanations appreciated

2. ## Re: [probability] any help with this challenging problem?? explanations appreciated

In any two by two sub-grid, there are $4^4= 64$ equally likely "configuration". Only one such configuration gives a circle.

3. ## Re: [probability] any help with this challenging problem?? explanations appreciated

i got it, thanks for your help.