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Question
If nP4 = 12(nP2), find n.
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Solution
Given that nP4 = 12(nP2)
n(n – 1) (n – 2) (n – 3) = 12n(n – 1)
Cancelling n(n – 1) on both sides we get
(n – 2) (n – 3) = 4 × 3
We have product of consecutive number on both sides with decreasing order.
n – 2 = 4
∴ n = 6
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