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    There are 16 different coloured marbles in bag 1.

    12 of the 16 marbles are then picked at random and put in a separate bag (bag 2).

    I then pick 4 marbles at random out of these 12 (bag 2).

    I like 4 of the 16 original differently coloured marbles. What are the odds that I like the colour of the 4 marbles that I have just picked from the 12 (bag 2)?
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    (Original post by X123)
    There are 16 different coloured marbles in bag 1.

    12 of the 16 marbles are then picked at random and put in a separate bag (bag 2).

    I then pick 4 marbles at random out of these 12 (bag 2).

    I like 4 of the 16 original differently coloured marbles. What are the odds that I like the colour of the 4 marbles that I have just picked from the 12 (bag 2)?
    There are two ways you can look at this using combinations that I can see:

    Either, it seems obvious that you are asked to choose a specific 4 from 16, since the intermediate choice is random.

    Or, consider probability of choosing 12 from 16 such that your 4 desired marbles are present, times the probability of choosing the specific 4 from 12.
 
 
 
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