Question

A set contains (2n+1) elements. The number of sub sets of this set which contains more than'n' elements is

• A. $2^{n-1}$
• B. $2^n$
• C. $2^{n+1}$
• D. $2^{2n}$

Answer 1

The correct option is D $2^{2n}$

${}^{2n+1}{C}_{n+1}{+}^{2n+1}{C}_{n+2}+.....{+}^{2n+1}{C}_{2n+1}=\frac{2^{2n+1}}{2}=2^{2n}$