Only those with high IQ can solve baffling brainteaser set in school classroom

A brainteaser has sparked a statement connected societal media arsenic users effort to fig retired the close reply - but galore person been forced to admit decision arsenic it's excessively challenging

People person been near scratching their heads implicit a baffling brainteaser aimed to uncover whether you person a precocious IQ oregon not. The puzzle asks players to enactment retired a maths question to guarantee each students successful a teacher's people person a prize astatine the extremity of the school twelvemonth for each their hard work.

Shared connected Reddit, it reads: "A teacher has an beforehand maths people containing 7 students. Every people for the full twelvemonth ends with the teacher putting a random fig from 1-7 connected their heads (they tin person the aforesaid fig arsenic idiosyncratic other successful the class, everyone could get a 5 for example).

"The students are allowed to look astatine each others numbers, but not communicate. They past person to conjecture what fig is connected their head. As agelong arsenic astatine slightest 1 pupil guesses correctly each class, they volition beryllium taken retired for pizza astatine the extremity of the year.

"All the students emotion pizza, particularly good earned pizza, truthful what strategy tin they employment to warrant they get it? Their conjecture is to beryllium written down, and the teacher takes it from their desk." While astir users tried and failed to enactment retired the close answer, others asked for clues to assistance them travel up with a solution.

One idiosyncratic asked: "Are the students allowed to not guess? Would the different students spot the anterior students not guessing?" While idiosyncratic other added: "I don't recognize however this is possible, the numbers are autarkic from each different and nary connection is allowed. So looking astatine the different students' numbers wouldn't springiness you immoderate accusation connected your number."

A 3rd idiosyncratic said: "Would determination beryllium nary different signifier of connection either? So could you accidental each students wholly blind, deaf, nary consciousness of time, thing and lone get the accusation of the different students fig by Morse codification tipping connected their hand?

"I person a solution erstwhile they are capable to spot the others writing, not what they constitute successful immoderate mode but successful which bid they are writing. Like if the sum of the 6 different numbers is even, pupil A starts writing, if not helium waits etc." Providing a hint, the archetypal poster said: "With conscionable 2 classmates this would beryllium casual capable (and the numbers lone 1 oregon 2).

"If pupil A writes down the fig connected pupil B's head, and pupil B writes down the fig not connected pupil A's head, 1 of them volition correctly conjecture the fig connected their ain head."

Sharing the close answer, a last idiosyncratic said: "The nth pupil assumes that the sum of each the numbers is n modulo 7. Since helium knows the numbers connected everyone else's head, helium tin enactment retired his ain fig utilizing that. Now if the sum is m modolu 7, past the mth student's presumption was correct, truthful helium managed to enactment retired his ain fig correctly. Success! Note that:

1. We person 7 students which is precisely capable to screen each possibilities mod 7.

2. Everyone else's presumption was incorrect truthful they each had incorrect answers. That doesn't substance since we lone needed 1 idiosyncratic to person the close answer."