How many socks take from the shelf to ensure that at least 2 of them have the same colour?
Solution 1
In the worst case, you may pick 6 socks each of a different color. So in order to get at least two socks on the same color, you need to pick at least 7 socks. It's a simple application of the Pigeon hole principle.
Solution 2
Hint: In the worst case scenario, you select from a different pair each time until you run out of pairs, then select one more sock. Only if you select this many socks, are you guaranteed to have at least a matching pair.
Solution 3
Seven. Worst case: You get one of each color (six), then the seventh must match one of the others.
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helloworld
Updated on December 07, 2020Comments

helloworld almost 3 years
I'm a little unsure on how to approach this question:
A drawer shelf contains 6 pairs of socks, each pair a diff color How many socks should be taken from the shelf to ensure that at least 2 of them are of the same?
Could I use a combination for this? $C(6, 2) = 15$? Thanks in advance!