Question

Hey there Brainliacs, try and solve this question...

What is the number of ways in which one can colour the squares of a 4 × 4 chessboard with colours red and blue such that each row as well as each column has exactly two red squares and two blue squares.

Do not copy.

I want detailed explanation.

The best answer would be marked as brainliest.

Good luck trying...​

Answer 1

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Number of ways of arranging 2R and 2B in 1st row In the first column the remaining entries can be filled in 3 ways. In the column in which the element in (1, 1) position repeats in first row, we can fill in 3 way (1 + 2)...

Total ways = 4/(2!)²×3 [1+2!×2]

= 90

mark it brainlist

Answer 2

Question:-

What is the number of ways in which one can colour the squares of a 4 × 4 chessboard with colours red and blue such that each row as well as each column has exactly two red squares and two blue squares.

$\huge\boxed{ \fcolorbox{yellow}{yellow}{solution}}$

_________________________

No. of total ways

= 4!/(2!)² ×3×[1+2!×2]

= 90