Question 45
Permutation and CombinationIf nP3 − 6(nC4) = 0, find the value of n.
- A.5
- B.6
- C.7
- D.8
Show the answer and explanation
Answer: C (7)
Explanation
n(n − 1)(n − 2) = 6 × n(n − 1)(n − 2)(n − 3)/24, so 1 = (n − 3)/4 and n = 7.
If nP3 − 6(nC4) = 0, find the value of n.
Answer: C (7)
n(n − 1)(n − 2) = 6 × n(n − 1)(n − 2)(n − 3)/24, so 1 = (n − 3)/4 and n = 7.