Passage: Consider the square in the figure. Let be the points of intersections (dots in the picture) in some order. We say that and are friends if they are adjacent along a row or along a column.

Question

Passage: Consider the  square in the figure. Let  be the points of intersections (dots in the picture) in some order. We say that  and  are friends if they are adjacent along a row or along a column. Assume that each point  has an equal chance of being chosen.

Question: Two distinct points are chosen randomly out of the points . Let  be the probability that they are friends. Then the value of  is

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More questions from this chapter