Can You Solve The Consecutive Numbers Puzzle?

Brilliance | Dec. 13, 2017

This brain teaser from puzzle master Presh Talwalkar of the MindYourDecisions YouTube channel seems impossible. Spoiler alert: This brain teaser is entirely solvable. Scroll down to read the puzzle, and to get the answer. Good luck!

Here's The Puzzle

Alice and Bob are each told a number, but neither knows the other's number. Both of the numbers are positive and consecutive. In the room with Alice and Bob, there is a clock that dings every minute. Someone can guess the other's number only at the ding of that clock, but they can also remain silent. If someone correctly guesses the other's number on the first try, both people $1 million.

There is a way to win without any form of communication between Alice and Bob, and, duh, without cheating. It's completely logical and can guarantee a win on the first try. How can they do it? Watch the video below to find out.

Here's The Answer

Suppose Alice is told the number N. She hears the clock ding N-1 times, so she knows that Bob was told N+1. Therefore, on the next ding, she can correctly guess Bob's secret number. If we're dealing with small numbers, however, it can be played differently. If Alice was told 1, she knows Bob was told 2 because 0 is not a positive (or negative) number. Watch the video above for a more in depth explanation of this logic puzzle. Did you get it?

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