Particles of masses m, 2m, 3m ... nm gram are placed on the same line at distance l, 2l, 3l, ..., nl cm from a fixed point. The distance of centre of mass of the particles from the fixed point in cm is

Options

A. `((2n+1)l)/(3)`
B. `(l)/(n+1)`
C. `(n(n^(2)+1)l)/(2)`
D. `(2l)/(n(n^(2)+1))`

Answer

A