Mind Your Decisions

How Many Squares Are In This Picture? Sunday Puzzle

Can you count the number of squares in this picture? Check out the video for a visual explanation that counts every single square. How Many Squares Are In This Picture? Or keep reading…

- 1 month, 6 days, 17 hours, 4 minutes ago

The Test-Taker’s Dilemma – Game Theory Tuesdays

image by Alberto G.. CC BY 2.0 Here’s a problem an economics professor might include on an exam. Think about what you would do. ———– You have a chance to earn…

- 1 month, 1 week, 5 days, 11 hours, 22 minutes ago

Physics Riddle – Faster Than The Speed Of Light?

Consider two trains that are 100 km apart and moving directly towards each other. If each train moves at 50 km per hour, how quickly will the two trains meet? The problem can be solved by…

- 1 month, 1 week, 6 days, 17 hours, 22 minutes ago

Calculate the day of the week for every date in 2016 (and until 2099)

Happy New Year! As you get used to writing the year 2016, here is a tip that can help you adjust to the new calendar year. You will be able to figure out the day of the week just from…

- 1 month, 2 weeks, 2 days, 26 minutes ago

This Question Stumped 75% of PhD Economists – Game Theory Tuesdays

Today’s problem is not about game theory but rather a question about opportunity costs, a concept that is taught in introductory economics courses. This question was answered…

- 1 month, 2 weeks, 5 days, 11 hours, 13 minutes ago

Number Of Ways To Divide Coins Interview Question – Sunday Puzzle

How many ways are there to divide 11 identical coins to 3 people? (Since the coins are identical, only the total number of coins given to each person matters, so one division might be 5…

- 1 month, 2 weeks, 6 days, 17 hours, 7 minutes ago

How To Split A Cake Fairly Using Math – Game Theory Tuesdays

How can 2 people split up a cake evenly? What about 3 people, or even N people? These are examples of fair division problems in game theory. There are mathematical methods known as…

- 1 month, 3 weeks, 5 days, 11 hours, 19 minutes ago

Squaring Numbers With Only 1s – Sunday Puzzle

What is the value of 111111111111111×111111111111111? Solve without a calculator. (There are 15 digits of 1). I have presented a video that explains an interesting pattern when you…

- 1 month, 3 weeks, 6 days, 17 hours, 19 minutes ago

The Best Way To Play Memory (Card Game) According To Math – Game Theory Tuesdays

The card game memory, aka concentration, is a children’s game that tests visual recall ability. There are n pairs of cards face down. The first player flips over 2 cards to make a…

- 2 months, 5 days, 11 hours, 25 minutes ago

Divide By 19 Mental Math Trick – Sunday Puzzle

What is 4/19? We can find the decimal expansion using a clever trick (which is described in my book The Best Mental Math Tricks). I heard about this technique as an example of Vedic…

- 2 months, 6 days, 17 hours, 56 minutes ago