NDA2011MathematicsPermutation and CombinationActual
What is the total number of combinations of n different things taken 1,2,3, , n at a time?
Options
- A2^ n+1
- B2^ 2 n+1
- C2^ n-1
- D2^n-1
Correct answer
D. 2^n-1
Step-by-step solution
The correct answer is option (D).