Tip:A–D to answerE for explanationV for videoS to reveal answer
If n and r are integers such that 1≤r≤n, then the value of n(n−1Cr−1) is:
- A.
nCr
- B.
r(nCr)
(Correct Answer) - C.
n(nCr)
Explanation
X=n((r−1)!×((n−1)−(r−1))!(n−1)!)
Multiply r to numerator and denominator:
Explanation
X=n((r−1)!×((n−1)−(r−1))!(n−1)!)
Multiply r to numerator and denominator:
