Black and White Marble Puzzle

The above is a simple math question which should be solved within 30 seconds….

Question :

There are three bags, each containing two marbles.

Bag A contains two white marbles,
Bag B contains two black marbles,
and Bag C contains one white marble and one black marble.

You pick a random bag and take out one marble.

It is a white marble.

What is the probability that the remaining marble from the same bag is also white?

Did you manage to solve it within 30 seconds ?   [ Scroll down for the answer  ]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer :

Probability of remaining marble in same bag is white is 2/3  (Not 1/2).

How is the answer derived?

We know that Bag B is out as it contains 2 black marbles, so that left us with the following 3 possibilities,

Possibility 1) You chose Bag A and took out White marble 1. The next marble will be white.

Possibility 2) You chose Bag A and took out White marble 2. The next marble will be white.

Possibility 3) You chose Bag C and took out White marble. The next marble will be black.

Hence, the probability of the remaining marble being white is 2/3.

If your answer is 1/2. You need to practice more puzzles   😉

 

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Have Fun !!   🙂