The arithmetic mean of nC0,nC1,nC2....nCn is
(A)2^n/n
(B)2^n-1/n
(C)2^n/n+1
(D)2^n-1/n+1
We know that
(1+x)n=Cn0+Cn1x+Cn2x2+....+Cnrxr+....+Cnnxn
Putting x=1 we get
Cn0+Cn1+Cn2+....+Cnr+....+Cnn=2n
Hence arithmetic mean of Cn0,Cn1,Cn2,....Cnn is
2nn+1