Let $S _ { n }$ denote the sum of first $n$-terms of an arithmetic progression. If $S _ { 10 } = 530 , S _ { 5 } = 140$, then $S _ { 20 } - S _ { 6 }$ is equal to: (1) 1862 (2) 1842 (3) 1852 (4) 1872
Let $S _ { n }$ denote the sum of first $n$-terms of an arithmetic progression. If $S _ { 10 } = 530 , S _ { 5 } = 140$, then $S _ { 20 } - S _ { 6 }$ is equal to:\\
(1) 1862\\
(2) 1842\\
(3) 1852\\
(4) 1872