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Question
If nC8 = nC2, find nC2.
Solution
nC8 = nC2 = nCn - 2
nC8 = nCn - 2
8 = n - 2
∴ n = 10
∴ nC2 = 10C2 = `(10!)/(2!(10 - 2)!) = (10!)/(2!8!)` = `(10 xx 9 xx 8!)/(2 xx 1 xx 8!) = 45.`
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