don steward
mathematics teaching 10 ~ 16

Wednesday, 15 June 2011

baby socks

baby socks, looking like shoes, come in three colours
there are lots of these in a drawer, all jumbled up
and it's dark, very dark

(i) how many socks do I need to pick out to be sure of having 2 of one kind?

how many to be sure of having (ii) 3 of one kind? (iii) 4 of one kind? (iv) n of one kind?

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