Consider the 6 × 6 square in the figure. Let A 1 , A 2 , … , A 49 be the points of intersections (dots in the picture) in some order. We say that A i and A j are friends if they are adjacent along a row or along a column. Assume that each point A i has an equal chance of being chosen. (There are two questions based on PARAGRAPH " II " , the question given below is one of them) Two distinct points a

Step-by-step solution

Given, We have to choose two distinct points randomly, Now number of ways of selecting 2 adjacent dots in row will be = 6 as if you pick any dot then you have pick second dot from remaining 6 dots, so total ways will be 1 × C 1 6 = 6 Similarly, number of ways of selecting 2 adjacent dots in column = 6 ∴   Number of ways of selecting 2 adjacent dots from the given diagram we will = 6 × 7 + 6 × 7 = 84 So, probability is given by, p = 84 C 2 49 = 84 × 2 49 × 48 ⇒ 7 p = 7 &#215