Today Puzzle #755
Puzzle No. 755 鈥� Friday 5 June 2020
I am given 12 coins labelled A to L. Eleven of them are the same weight, but one of them is not, and I do not know if it is heavy or light. I am given an ordinary balance and three weighings to determine which is the fake coin and whether it is heavy or light. On each weighing the labels on the coins in each scale pan must spell a common English word. How do I do this?
Today’s #PuzzleForToday has been set by School of Mathematics and Statistics at the University of Sheffield.
Click here for the answer
A possible solution is to weigh HEAD against GLIB, BLED against JACK and CALF against HIKE. Each weighing gives one of three possible outcomes: right heavy, left heavy or balanced. So there are 27 possible combinations. Three of these will never occur, and the other 24 correspond to the 24 different scenarios, as can be easily checked.
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