Marbles 2: Green

Level pending

There are 35 marbles in a bag. Of which 3 are white, 5 are blue, 8 are red, 9 are green and 10 are yellow. The marbles will be taken out at random until a green marble is taken out.

How many marbles will need to be taken out at most, to guarantee that we will get a green marble?


The answer is 27.

Anthony Teo by Anthony Teo , 21, Netherlands

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2 solutions

Eghar Anugrapaksi
Dec 20, 2014

For a worst case let the green marble is taken out last, so we have 26 other non-green marbles, then in our 27th chance we have our green marble.

3 Helpful 0 Interesting 0 Brilliant 0 Confused
Eva Donlon
Jan 12, 2015

If all came to all, then you would have to pick 26 marbles that aren't green and only then be sure of picking a green one as all=35, non-green=26. 35-26 equals 9 which is the amount of green marbles.

1 Helpful 0 Interesting 0 Brilliant 0 Confused

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