The Australian Mathematical Society Gazettes Puzzle Corner is a regular column with entertaining mathematical puzzles, heres an example: "Picky padlocks An ancient scroll is kept in a chest, which is locked by a number of padlocks. All padlocks must be unlocked in order to open the chest. Copies of the keys to the padlocks are distributed amongst 12 knights, such that any group of 7 or more knights can open the chest should they choose to do so, but any group of less than 7 cannot. What is the minimal number of padlocks required to achieve this?" You can find the Puzzle Corner 31 online at: http://www.austms.org.au/Publ/Gazette/2013/Mar13/Puzzle.pdf Check it out when you feel like trying out some fun problems, and be sure to email your solutions to ivanguo1986@gmail.com. A $50 book voucher is up for grabs for the best submission. The deadline for submissions is 1 May 2013. The solutions will appear in the July 2013 issue of the Gazette. Thank you Ivan Guo