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Question
Evaluate `("n"!)/("r"!("n" - "r")!)` when n = 6, r = 2
Solution
n = 6 , r = 2
`("n"!)/("r"!("n" - "r")!) = (6!)/(2!(6 - 2)!)`
= `(6!)/(2!4!)`
= `(6 xx 5xx 4!)/(2 xx 1 xx 4!)`
= `(6 xx 5)/2`
= 3 × 5
= 15
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