Question

Consider the 6 x 6 square in the figure. Let A1, A2, ........, A49 be the points of intersections (dots in the picture) in some order. We say that Ai and Aj are friends if they are adjacent along a row or a column. Assume that each point Ai has an equal chance of being chosen. Let i p be the probability that a randomly chosen point has i many friends, i = 0,1,2,3,4. Let X be a random variable such that for i = 0,1,2,3,4, the probability P(X = i) =pi. Then the value of 7E(X) is

Answer 1

The value of 7 E(X) is 24.