# Category Archives: Test your intuition

## Test your intuition 24: Which of the following three groups is trivial

Martin Bridson We have three finitely presented groups A is generated by two generators a and b and one relation   B is generated by three generators a, b, c and three relations ,    . C is generated by four generators a, b, c, d … Continue reading

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## Test Your Intuition (23): How Many Women?

How many women can you find on this poster announcing the 25th Jerusalem School in Economics Theory devoted to Matching and Market Design? Please respond to the poll:

Posted in Economics, Test your intuition | Tagged | 5 Comments

## Answer to Test Your Intuition (22)

Indeed, most people got it right! Bundling sometimes increases revenues, sometimes keeps revenues the same, and sometimes decreases revenues. In fact, this is an interesting issue which was the subject of recent research effort. So here are a few … Continue reading

## Test your intuition (22): Selling Two Items in a Bundle.

One item You have one item to sell and you need to post a price for it. There is a single potential buyer and the value of the item for the buyer is distributed according to a known probability distribution. It … Continue reading

Posted in Economics, Test your intuition | Tagged | 1 Comment

## Auction-based Tic Tac Toe: Solution

Reshef, Moshe and Sam The question: (based on discussions with Reshef Meir, Moshe Tennenholtz, and Sam Payne) Tic Tac Toe is played since anciant times. For the common version, where the two players X and O take turns in marking … Continue reading

Posted in Games, Test your intuition | Tagged | 6 Comments

## Test Your Intuition (21): Auctions

You run a single-item sealed bid auction where you sell an old camera. There are three bidders and the value of the camera for each of them is described by a certain (known) random variable: With probability 0.9 the value … Continue reading

Posted in Economics, Games, Test your intuition | | 4 Comments

## Oz’ Balls Problem: The Solution

A commentator named Oz proposed the following question: You have a box with n red balls and n blue balls. You take out each time a ball at random but, if the ball was red, you put it back in the box and take out … Continue reading

Posted in Probability, Test your intuition | | 1 Comment

## Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun

Yeshu Kolodni and Lord Kelvin The question In 1862, the physicist William Thomson (who later became Lord Kelvin) of Glasgow published calculations that fixed the age of Earth at between 20 million and 400 … Continue reading

Posted in Geology, Physics, Test your intuition | 4 Comments

## 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