Mathematics

Problem

The sum of the first

2n

terms of an A.P. is

x

and the sum of the next

n

terms is

y

, its common difference is : (a)

\frac{x-2y}{3n^2}

(b)

\frac{2y-x}{3n^2}

(c)

\frac{x-2y}{3n}

(d)

\frac{2y-x}{3n}