You and two other people have numbers written on your foreheads. You are all told that the three numbers are primes and that they form the sides of a triangle with a prime perimeter. You see 5 and 7 on the other two heads and both of the other people agree that they cannot deduce the number on their own foreheads.
What is the number written on your forehead?
I think that i have found the answer to the riddle:prime perimeter!
it say that three numbers are listed on each others heads.Two of
the numbers are 5 and 7.It also says that
the total perimeter is a prime number. I think
that shape is a right triangle , and
not an equalateral. The numbers imply that, since they are
not equal.5 plus seven equals 12. the bottom halve will end up as 5 if
you do the math . 5+5+7=17, which just happens to be a prime number!
So....17 is the final answer!!
Posted by jason
on 2005-03-26 02:58:33