Question

100
DProblem : Two squares are chosen at random on a chess board. Show that the probability
that they have a side in common is
1/18​

Answer 1

Answer:

two squares can be chosen in 64C2 ways= 64*63/2= 2016

(Try to visualize an actual chessboard)

now if we consider vertically say in the first column we can get 7 pairs of squares where each pair will have one common side. similarly for the second third….and eight column = 7*8=56 possibilities.

Again if we consider horizontally say in the first row then we get 7 pairs of squares where each pair will have one common side. Same goes for the second third ….eight rows = 7*8 =56 possibilitie