NTA Abhyas JEE Main2020MathematicsPermutation and CombinationPractice
A rectangle with sides 2 m - 1 and 2 n - 1 is divided into squares of unit length. The number of rectangles that can be formed with both the sides of odd length is
Options
- Am 2 n 2
- Bm n m + 1 ( n + 1 )
- C4 m + n - 1
- DNone of these
Correct answer
A. m 2 n 2
Step-by-step solution
Number of rectangles possible is = (Number of ways to choose a horizontal side of odd length).(Number of ways to choose a vertical side of odd length) 1 + 3 + 5 + ..... + 2 m - 1 1 + 3 + 5 + ..... + 2 n - 1 = m 2 n 2