Puzzle #27: The goblin game
26 October 2019
Posted by on
From New Scientist #3253, 26th October 2019 [link] [link]
Annie and Beth are about to play “Goblin”. Like snakes and ladders, it is a game played on a 10 × 10 grid of squares numbered from one to 100. Players start with their counter off the board (next to square one) and take it in turns to roll a single die, aiming to be the first to get to square 100.
However, instead of snakes or ladders, there is just one hazard: a goblin. Each player gets one goblin and is allowed to place it on any square they want (apart from square 100) before the game starts.
If you land on your opponent’s goblin, you lose, and the same goes for your opponent. If a player lands on their own goblin, they are safe. If neither player lands on a goblin, the first to get to 100 wins (an exact final roll isn’t required, just getting to the 100 square is enough).
Annie, who has never played before, decides to place her goblin on square 31, because that is her lucky number.
Where should Beth place her goblin to have the maximum chance of winning?