AboutRohit Agarwal Expertise I can answer questions related to numbers and logic easily. However I sometimes face problems when solving questions that require a lot of creative thinking. I am not good at puzzles which involve a play with words, so please don't ask me to solve such puzzles for you.
Experience I have read a couple of good books containing puzzles and can now claim to have an "expert" in this field. I have been invited to become a member of Mensa.
Organizations INDIAN INSTITUTE OF TECHNOLOGY, DELHI
Education/Credentials Currently doing Dual Degree (B.Tech M.Tech) in Electrical Engineering Department from INDIAN INSTITUTE OF TECHNOLOGY, DELHI
Awards and Honors Numerous certificates recognizing my ability in Mathematics and Logical Thinking
Question A wealthy ginger is searching for a suitor for his daughter, so he collects the three smartest men in town. He sits them in a circle and tells them he is going to put a red mark or a white mark on each of their heads while their eyes are closed. He puts a red mark on all three and tells them to open their eyes. He then asks them if they see a red dot then they should raise their hand. They all raise their respective hands. He then says that if you know the colour dot that is on your forehead, then stand up. After a few minutes one man stands and says the correct colour. How does he know?
Thank you so much whoever answers this.
Answer There are 4 cases
All White:
Negated as all of them can see atleast one red mark
2 White 1 Red:
Negated as all of them can see two red marks
Now everyone knows that everyone knows that there is atmost 1 white
1 White 2 Red:
If this was true, and assuming that there is atmost 1 white, then the person who can see 1 white will know that the mark on his forehead is red. Since this doesn't happen, this also is negated.
