Question -
Answer -
Given:
P (9, r) = 3024
By using the formula,
P (n, r) = n!/(n – r)!
P (9, r) = 9!/(9 – r)!
So, from the question,
P (9, r) = 3024
Substituting theobtained values in above expression we get,
9!/(9 – r)! = 3024
1/(9 – r)! = 3024/9!
= 3024/(9×8×7×6×5×4×3×2×1)
=3024/(3024×5×4×3×2×1)
= 1/5!
(9 – r)! = 5!
9 – r = 5
-r = 5 – 9
-r = -4
∴ The value of ris 4.