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Logic Problem

Logic Problem - 10 December

Logic Ball Bag ProblemThere is a bag which have 21 blue balls and 23 red balls. You also have 22 red balls outside the bag.

Randomly remove two balls from the bag.
* If they are of different colors, put the blue one back in the bag.
* If they are the same color, take them out and put a red marble back in the bag.

Repeat this until only one marble remains in the bag.

What is the color of the sole marble left in the bag ?

For Solution : Click Here


  1. can any one explain how it should be blue?

  2. Can anyone explain from where Marble came when we have Blue & Red Balls?????

  3. Blue...
    For every different ball pair a blue ball is kept back and red taken out.
    For every same ball pair red is replaced with the balls.

    As the no. of blue and red balls are odd,
    There will always be 1 left in both if we remove them in same ball pairs. and when we remove the last 2 there will be blue.

    If we remove them in different ball pairs,
    then we anyway increase the blues and ion the end only blue remains.

    The odd no. of balls causes the last ball to be blue everytime.

  4. The Greeks want there (MARBELS) back!!!??
    And there are balls or marbles£££
    Can someone explain.?
    Because they don't know what TAX IS. HA HA,

  5. Didn't know where the marbles were coming from!!!