1
$\begingroup$

I'm trying to solve this puzzle. Numbers are at triangle, and I have to solve ?-mark:

       5
     6   1
   7       2
  5  ?   7   5

Based on solutions it should be ?=7. But I don't understand the reason for this

I also put pic of it.Triangle quiz

$\endgroup$
  • $\begingroup$ There could be dozens of answers with a reasonable logic. For instance, it should be 2 as in every little triangle there are two numbers whose sum is the third. $\endgroup$ – Arnaud Mortier Sep 15 at 6:50
  • $\begingroup$ Can you then name one explanation, why the answer would be seven? $\endgroup$ – No name Sep 15 at 6:59
  • 1
    $\begingroup$ What is the source for this puzzle? A textbook, competition, ... ? $\endgroup$ – Rand al'Thor Sep 15 at 7:03
  • $\begingroup$ Yes, for instance: every number should appear an odd number of times. $\endgroup$ – Arnaud Mortier Sep 15 at 7:07
  • 1
    $\begingroup$ Thanks Arnaud Mortier! Good explanation $\endgroup$ – No name Sep 15 at 7:10
4
$\begingroup$

It is:

7. Start with $5,5,5$. The sum is $15$. Move each circle clockwise one step. You now have $1,7,7$, again the sum is $15$. Moving clockwise again you have $2,?,6$. For the sum to be $15$, $?=7$.

$\endgroup$
  • $\begingroup$ Thanks! Very interesting $\endgroup$ – No name Sep 15 at 7:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.