Česky: Jablka jsou všeamericky úspěšná potravi...
Image via Wikipedia

Four friends Matt, James, Ian and Barry, who all knew each other from being members of the Automattic, called Automatticians, sat around a table that had a dish with 11 apples in it. The chat was intense, and they ended up eating all the apples. Everybody had at least one apple, and everyone know that fact, and each automattician knew the number of apples he ate. They didn’t know how many apples each of the others ate, though. They agreed to ask only questions that they didn’t know the answers to:

Matt asked: Did you eat more apples than I did, James?

James: I don’t know. Did you, Ian, eat more apples than I did?

Ian: I don’t know.

Barry: Aha!! I figured out..

So, Barry figured out how many apples each person ate. Can you do the same?


Matt: 1 Apple

James: 2 Apples

Ian: 3 Apples

Barry: 5 Apples

The Logic

Matt could not have eaten 5 or more. James could not have eaten only one or he would have known that he hadn’t eaten more than Ian. Neither could he have eaten 5 or more. He could have eaten 2 or 3 or 4 apples. Ian figures this out, although he still doesn’t know if he ate more than James. This mean that Ian must have eaten 3 or 4 apples. Barry can only deduce the other amounts if he ate 5 apples. And the rest, in order to add up to 11 , must have eaten 1, 2 and 3.

Inspired from a childhood heard puzzle.

Related Articles Found on this Blog:

    1. The first worthy comment on this topic. Actually the point, I assumed, that one will ask a question, whose answer he doesn’t know, makes the logic and provides the answer. Other answers might be possible- but As I said, it is inspired by a childhood heard puzzle, I thought not to make more changes than original. Thanks for your comment.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

You May Also Like

Test your counting skills with Branifyd game for Android

Without basic operations of counting, like Addition, Subtraction, Multiplication and Division, it is not possible to imagine math problems. Counting is the base of human life. A student, whether he’s a math major or not, must be good at counting numbers.  The counting ability builds from experience and is definitely a time taking process.   Larger you have given time…

Triangle Inequality

Triangle inequality has its name on a geometrical fact that the length of one side of a triangle can never be greater than the sum of the lengths of other two sides of the triangle. If $ a$ , $ b$ and $ c$ be the three sides of a triangle, then neither $ a$ can be greater than $…

Difference Paradox

Consider two natural numbers $n_1$ and $n_2$, out of which one is twice as large as the other. We are not told whether $n_1$ is larger or $n_2$, we can state following two propositions: PROPOSITION 1: The difference $n_1-n_2$, if $n_1 >n_2$, is different from the difference $n_2-n_1$, if $n_2 >n_1$. PROPOSITION 2: The difference $n_1-n_2$, if $n_1 >n_2$, is the same…

Google Chrome wants you to switch to HTTPS. Do it for free!

In the beginning of this year, Google, eh, Google Chrome announced that they will be discouraging non-secure HTTP websites. Basically Google prefers secured websites in search rankings and after the announcement the measures were surely going to be tighter. But this time it is not just about the result rankings, if you own a website, especially a business website, you must…

The ‘new’ largest known Prime Number

Great Internet Mersenne Prime Search (GIMPS) group has reported an all new Mersenne Prime Number (a prime number of type $2^P-1$) which is, now officially the largest prime number ever discovered. This number is valued to a whopping $2^{74207281}-1$ and contains 22,338,618 digits. It is quoted as M747207281 and is almost 5 million digits longer than the previous record holding prime number…