I have a Puzzle consisting of pieces.
What is the minimum number of pieces I have to draw randomly from a pile to be guaranteed that there is at least one square (in the solved puzzle) whose pieces all have been drawn?
Details and Assumptions:
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
91 is not enough: if all the nine 3i-3j pieces are missing (labeling the pieces like the entries of a matrix), then each 3 × 3 square will miss exactly one piece. But 92 suffices: Consider nine disjoint 3 × 3 squares; at least one of them will be complete.