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# Noobs Weekly: Release II

Week 2: Infinite Quarter Sequence

You are wearing a blindfold and thick gloves. An infinite number of quarters are laid out on a table of infinite area. 20 of these quarters are tails and the rest are heads. How can you can split the quarters into 2 piles where the number of tails quarters is the same in each? You are allowed to move the quarters and to flip them, but you can never tell what state a quarter is currently in.

s

2 years, 5 months ago

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Take 20 of the quarters, flip them over and put them in one pile. The other coins go into one infinite pile. If there were $$x$$ tails among the finite pile when picked, there will be $$20 - x$$ tails in the infinite pile. As all 20 quarters that were picked have been flipped over, the finite pile will also have $$20 - x$$ tails. $$\blacksquare$$ · 2 years, 5 months ago