C9 From the figure it is clear that the given square of size 3 x 3
can be formed by using four consecutive horizontal and 4 consecutive vertical lines, which can be done in
6
C1 ×
6
C1 = 36 ways Basically you can make 6 squares of size 3 x 3 in vertical direction and 6 squares of the size 3 x 3 in horizontal direction, Hence total 6 x 6 = 36 squares can be chosen. ∴ The required probability =