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JEE MATHEMATICS MCQ: PERMUTATIONS

1 Easy

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Understanding +4 | -1

The value of

\sum \limits_{r = 1}^n \,\frac{{{\;^n}{P_r}}}{{r!}}

is

View answer and explanation

Correct option: B

{2^n} - 1

Option B (

{2^n} - 1

) is correct because the given summation is equivalent to the binomial expansion of

(1+1)^n

excluding the first term.

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