Question

The number of non congurent rectangle that can be formed on a chessboard, is

(A) 30

(B) 32

(C) 33

(D) 36

Answer 1

Correct option (D) 36

Explanation:

Rectangle with side length

1 × 1, 1 × 2, 1 × 3,..........1 × 8 → 8

2 × 2, 2 × 3, 2 × 4,..........2 × 8 → 7

∴ 8 × 8 → 1

Total = 1 + 2 + 3 + ...+ 8

8(9)/2 = 36