Search This Blog

Citi Bank Interview Puzzle

Citi Bank Interview Puzzle - 19 July

There are three boxes labelled as Red Balls, Black Balls and Red and Black Balls. Each one of the box is labelled incorrectly. You have just one chance to pick up from any box and then label the boxes correctly.

How will you do it?

For Solution : Click Here


  1. Red balls (rb) black balls (bb) red and black balls (rbb)

    Take a ball from rbb it contains one color either red or black, if it is red then the box marked bb contains rbb ( it cannot contain bb as bb is wrongly labbled)

    rbb=red (black)
    rb=black (red and black)
    bb=red and black (red)

    If you get black first time then the colours in bracket is the answer.

    If you open rb or bb you cannot solve this question.

    1. Pick 1 from box "R", if it's black, box "B" is two color, bob "RB" is red. If pick from "R" is two color, then bob "B" is RB, and bpb "RB" is black.