Question

Two small squares on a chess board are chosen at random. Probability that they have a common side is,

• A. 1/3
• B. 1/9
• C. 1/18
• D. None of these

Answer 1

Answer: (C)

1/18

Answer 2

The ere are 64 small squares on a chessboard.

⇒ Total number of ways to choose two squares

= ⁶⁴C₂ = 32.63

For favourable ways we must chosen two consecutive small

squares for any row or any columns

⇒ Number of favorable ways = (7.8)2

⇒ Required probability =$\frac { 7.8 .2 } { 32.63 } = \frac { 1 } { 18 }$