31 students in a row were numbered 1,2,...,31 in order. The teacher wrote down a number on the blackboard.

Student 1 said "the number is divisible by 1",
Student 2 said "the number is divisible by 2",
and so forth...until
Student 31 said "the number is divisible by 31".

The teacher remarked: "Very well pups, but two of you gave a wrong statement, and those two sit besides each other". Determine those two.

Every number is divisible by 1, so student 1 is correct.<br>
Students 2 and 31 can't both be wrong by the seating  rule. So...<br>
If student 2 is wrong, so is student 3.<br>
If student  31 is wrong, so is student 30.<br>
If students 2 and 31 are both right, (ie the number on the board is  62), it could be any pair from 3 to 30 inclusive.<br><br>I don't see the problem. Maybe I should go read the other comments, and or the solution.
 

Posted by bob909 on 2004-09-07 16:06:37