Question -
Answer -
Given:
nP4 = 360
nP4 can be written as P (n , 4)
By using the formula,
P (n, r) = n!/(n – r)!
P (n, 4) = n!/(n – 4)!
So, from the question,
nP4 = P (n, 4) = 360
Substituting theobtained values in above expression we get,
n!/(n – 4)! = 360
[n(n– 1) (n – 2) (n – 3) (n – 4)!] / (n – 4)! = 360
n (n – 1) (n – 2)(n – 3) = 360
n (n – 1) (n – 2)(n – 3) = 6×5×4×3
On comparing,
The value of n is 6.