NDA2011MathematicsPermutation and CombinationActual
5 books are to be chosen from a lot of 10 books. If m is the number of ways of choice when one specified book is always included and n is the number of ways of choice when a specified book is always excluded, then which one of the following is correct?
Options
- Am n
- Bm=n
- Cm=n-1
- Dm=n-2
Correct answer
B. m=n
Step-by-step solution
The correct answer is option (B).