Question

Find the total number o $f$ rectangles on a normal chessboard.

• A. ${}^8{C}_2\times {}^8{C}_2$
• B. ${}^8{C}_2+8C_2$
• C. ${}^9{C}_2\times {}^9{C}_2$
• D. ${}^9{P}_2\times {}^9{P}_2$

Answer 1

Answer: (C)

Total number of Rectangles in $n\times n$ chess board
$=n+1_{C_2}\times n+1_{C_2}$
$\therefore$ Total Number of Rectangles in $8\times 8$ chess Boord
$=9_{C_2}\times 9_{C_2}$