20 Challenging Job Interview Puzzles which every analyst should solve atleast once



What is answer for no. 20 problem.im verifying is this 10


Please provide a valid link to explore the problem. If possible, please describe the problem here directly instead of redirecting to another website.


I think is referring to this post:
to post

Regarding the answer to 20… I have an intuition but not sure yet. Need to think harder!