Comparison is needed. So its between A and E.
I prefer E than A. OA and OE pls?

Hi Ron, I have a doubt about your equation : Shouldnt it be x + 2x + 6x = 2*pi*r ( instead of 360 ??) Here we are adding the lenght of arcs and not degrees...though we shall get the same answer at the end as 40 as follows: x = (2/9)(pi*r) For AB we need to get 2x which is (4/9)(pi*r) (4/9)(pi*r) = (...

Answer should be C. The answer does not assume that the series begins from 1. It can start from any number. We need to check if the series has odd or even number of terms. Since the median is 20, the series shall always have ODD number of terms, we cannot have EVEN number of terms, in which case the...