Question
Question: <sup>n</sup>C<sub>0</sub> + 3.<sup>n</sup>C<sub>1</sub> + 5.<sup>n</sup>C<sub>2</sub> + ......... + ...
nC0 + 3.nC1 + 5.nC2 + ......... + (2n + 1)nCn =
A
2n
B
2n + n.2n –1
C
2n(n + 1)
D
None
Answer
2n(n + 1)
Explanation
Solution
S = nC0 + 3.nC1 + 5.nC2 + .......+ (2n + 1)nCn
2S=(2n+2)[nC0+nC1+...+nCn]+S=(2n+1).nC0+(2n–1).nC1+....+1.nCn
S = (n + 1). (2)n