If the sum of first n terms of an A.P. is 3n² + 2n, find its r^th term.

If p^th term of and A.P. is q and its q^th term is p, show that its r^th term is (p + q - r).

If the 5^th and 11^th terms of an A.P. are 16 and 34 respectively. Find the A.P.

For an A.P. the sum of its terms is 60, common difference is 2 and last term is 18. Find the number of terms in the A.P.