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# Category Archives: Test your intuition

## Test your Intuition/Knowledge: What was Lord Kelvin’s Main Mistake?

The age of the earth (Thanks to Yeshu Kolodny) We now know that the age of the earth is 4.54±1% Billion years. From Wikipedea: In 1862, the physicist William Thomson (who later became Lord Kelvin) of Glasgow published calculations that … Continue reading

Posted in Controversies and debates, Geology, Physics, Test your intuition
Tagged Earth, Geology, Lord Kelvin, Test your intuition
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## Taking balls away: Oz’ Version

This post is based on a comment by Oz to our question about balls with two colors: “There is an interesting (and more difficult) variation I once heard but can’t recall where: You have a box with n red balls … Continue reading

Posted in Guest post, Probability, Test your intuition
Tagged Oz, Probability, Test your intuition
14 Comments

## Answer to test your intuition (18)

You have a box with n red balls and n blue balls. You take out balls one by one at random until left only with balls of the same color. How many balls will be left (as a function of n)? … Continue reading

Posted in Probability, Test your intuition
Tagged Itai Benjamini, Probability, random permutation, Ronen Eldan, Test your intuition
3 Comments

## Itai Ashlagi, Yashodhan Kanoria, and Jacob Leshno: What a Difference an Additional Man makes?

We are considering the stable marriage theorem. Suppose that there are n men and n women. If the preferences are random and men are proposing, what is the likely average women’s rank of their husbands, and what is the likely average … Continue reading

## Test Your Intuition (19): The Advantage of the Proposers in the Stable Matching Algorithm

Stable mariage The Gale-Shapley stable matching theorem and the algorithm. GALE-SHAPLEY THEOREM Consider a society of n men and n women and suppose that every man [and every woman] have a preference (linear) relation on the women [men] he [she] knows. Then … Continue reading

## Test Your Intuition (18): How many balls will be left when only one color remains?

(Thanks to Itai Benjamini and Ronen Eldan.) Test (quickly) your intuition: You have a box with n red balls and n blue balls. You take out balls one by one at random until left only with balls of the same … Continue reading

Posted in Probability, Test your intuition
26 Comments

## Test Your Intuition (17): What does it Take to Win Tic-Tac-Toe

(A few more quantum posts are coming. But let’s have a quick break for games.) Tic Tac Toe is played since anciant times. For the common version, where the two players X and O take turns in marking the empty squares … Continue reading

## What does “beyond a reasonable doubt” practically mean?

(Motivated by two questions from Gowers’s How should mathematics be taught to non mathematicians.)

Posted in Law, Probability, Test your intuition
18 Comments

## Test Your Intuition (16): Euclid’s Number Theory Theorems

Euclid’s Euclid’s book IX on number theory contains 36 propositions. The 36th proposition is: Proposition 36.If as many numbers as we please beginning from a unit are set out continuously in double proportion until the sum of all becomes prime, … Continue reading

Posted in Algebra and Number Theory, Test your intuition
Tagged Euclid, Greek mathematics
16 Comments