If `S_(n)` denotes the sum of first n terms of an A.P., then
`(S_(3n)-S_(n-1))/(S_(2n)-S_(n-1))` is equal to

If S_(n) , denotes the sum of first n terms of a A.P. then (S_(3n)-S_(n-1))/(S_(2n)-S_(2n-1)) is always equal to

If S_n denotes the sum of first n terms of an A.P. and (S_(3n)-S_(n-1))/(S_(2n)-S_(2n-1))=31 , then the value of n is a. 21 b. 15 c.16 d. 19

If S_n denotes the sum of first n terms of an A.P. and (S_(3n)-S_(n-1))/(S_(2n)-S_(2n-1))=31 , then the value of n is 21 b. 15 c.16 d. 19

If S_n denotes the sum of first n terms of an A.P. and (S_(3n)-S_(n-1))/(S_(2n)-S_(2n-1))=31 , then the value of n is 21 b. 15 c.16 d. 19

If S_(n) denotes the sum of first n terms of an A.P. and S_(2n)= 3S_(n) , then (S_(3n))/(S_(n))=

If S_(n), denotes the sum of n terms of an A.P. then S_(n+3)-3S_(n+2)+3S_(n+1)-S_(n)=

If S_(n) denotes the sum of first n terms of an AP, then prove that S_(12)=3(S_(8)-S_(4)).

If S_(n) denotes the sum of first n terms of an AP, then prove that S_(12)=3(S_(8)-S_(4)).

S_(r) denotes the sum of the first r terms of an AP.Then S_(3d):(S_(2n)-S_(n)) is -

If S_n, denotes the sum of n terms of an A.P. , then S_(n+3)-3S_(n+2)+3S_(n+1)-S_n=