Enigmatic Code

Programming Enigma Puzzles

Tag Archives: by: Susan Bricket

Teaser 2907: Combinatorial cards

From The Sunday Times, 10th June 2018 [link]

On holiday once with lost luggage and trapped indoors, we decided to recreate our favourite card game. With limited resources, we used just seven cards and seven images (red heart, green tree etc.) with three images on each card. Remarkably, just as in the game at home, every pair of cards had exactly one image in common. Labelling the seven images from 1 to 7, the cards were as follows:

{1,2,4} {2,3,6} {1,3,5} {1,6,7} {2,5,7} {3,4,7} {4,5,6}

Interestingly, each image appears on just three cards.

Our original set of cards at home has eight images per card, each image appears on just eight cards and again the total number of images is the same as the number of cards.

What is that number?

Today’s bonus puzzle revisits one of the Sunday Times Teasers from 2018 that I found interesting.