A guy tells you: I will pick a random number between 0 and 100. I will give you X$ if you find the exact number. The rules are simple: You have to give me 1$ for every questions you ask about this number and I must only answer by YES or NO. What is the minimal amount I should give you to make sure you always make a profit? (X$)

First of all "OUCH!" as walking into a bar would have hurt! Secondly he never says how much he will pay if you guess the number correctly and so it could be $0 and so the minimum would be 0! Lewi

The minimum about You should give me is the number of Questions asked till telling the answers! It can be anywhere from $0 to $99, with regards to when he gets the answer!! ~ExP~

I think the max number of questions needed to know the answer is 7. So to guarantee a profit no matter what payout would need to be greater than $7.

yea its $7 because 100 is between 2^6 and 2^7 so a binary search on 100 items would require 7 guesses