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JEE MATHEMATICS MCQ: COMBINATIONS

1 Easy

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Application +4 | -1

If

a_n=\sum\limits_{{r=0}}^n \frac{1}{{ }^n C_r}

, then

\sum\limits_{{r=0}}^n \frac{r}{{ }^n C_r}

equals

View answer and explanation

Correct option: C

\frac{1}{2} n a_n

Option C is correct because it is derived from the properties of binomial coefficients and summation.

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