15) If nPs = 42nP3, n>4 find n.
Answers
Answered by
0
Step-by-step explanation:
n
P
5
=42n
P
3
(
(n−5)!
n!
)=42(
(n−3)!
n!
)
⇒(n−4)(n−5)=42
⇒n
2
−9n−22=0
⇒n=−2;11
As n should be positive and greater than 4
⇒n=11
Similar questions