JonC 101 / Brainteaser Collection / Difficulty 2/5 Questions
The basic setup for each problem is given below. For more details, hints, and a solution to each, click on the problem's title.
Title Difficulty Basic Setup

Four guys are attempting to cross over a chasm on a rickety old bridge in the middle of the night. Because it is so dark, the bridge can only be crossed with a lantern. Because the bridge is so unstable, only two people can cross the bridge at a time.

The guys do have one lantern with them that will allow them to cross, however, they are not all as nimble as each other. As a result, they take different lengths of time to cross the bridge. The respective times it takes for each to cross is 1min, 2min, 5min and 10min.

If two guys are walking across the bridge together with the lantern, they can only cross as fast as the slower of the two can.

Click to learn what IS the shortest time possible for all four to cross bridge What order should they go in to get all four of the guys across the bridge in the shortest total amount of time?


Assume you are placing dominoes on an 8x8 chessboard, such that each domino will cover exactly two squares of the chessboard. Can you cover every square of the chessboard with dominoes, without having any dominoes hanging off the side of the board?

With a little thought, the answer to the above question should obviously be "Yes." Now suppose, the two OPPOSITE corners of the chessboard are removed.

Can the remaining 62 squares of the chessboard be covered by dominoes without having any dominoes hanging off the board?


Queens in chess can "attack" in every linear direction. That is, a queen is considered to be "attacking" any piece which is on the same row, column or diagonal as the queen.

Can you place 8 queens on an 8x8 chessboard such that no queen is attacking any other queen?

brainteaser/difficulty2.htm | Page last updated $Date: 2003/11/30 09:12:49 $