Q.

The value of  C114+C314+C514+⋯+C1114 is

1 214-1  
2 214-14  
3 212  
4 213-14  

Ans.

(4)

C114+C314+C514+⋯+C1114

=(C114+C314+C514+⋯+C1314)-C1314

=214-1-C114=213-14