Find the rth term of an A.P., the sum of the whose first n term si `2n+3n^2`

If the first term of an A.P. is 2 and the sum of the first five terms is equal to one-fourth of the sum of the next five terms, find the 20th term.

If the first term of an A.P. is 2 and the sum of the first five terms is equal to one-fourth of the sum of the next five terms, find the sum of first 30 terms.

If the sum of first p terms of an A.P. is equal to the sum of the first q terms, then find the sum of the first (p+ q) terms.

Find the sum S_n of the cubes of the first n terms of an A.P. and show that the sum of first n terms of the A.P. is a factor of S_n .

Find the first six terms of the sequence whose first term is 1 and whose (n+1)th term is obtained by adding n to the nth term.

The sum of the first four terms of an A.P. is 56. The sum of the last four terms is 112. If its first term is 11, then find the number of terms.

If the sum of first 10 terms of an A.P. is 4 times the sum of its first 5 terms, then find the ratio of first term and common difference.

Find the sum of first n terms of an A.P. whose nth term is 3n+1.

Find the sum of an A.P. of :- 26 terms whose nth term is (2n + 1)/3 .