If the first and last terms of an A.P. are given, then the formula to find the sum is …….

4.If the first and last terms of an A.P.are 1 and 11 respectively and the sum of its terms is 30. find the number of terms in the A.P.

If the first and the last terms of an A.P. are -4 and 146 respectively and the sum of this A.P. is 7171 then its common difference is

The first and last terms of an A.P. are - 7 and 233 and the sum of the A.P. is 9153. Find the number of terms in the A.P.:

The first, second and last terms of an A.P. are a, b, c respectively, then the sum to first n terms is

If the first, second and the last terms of an A.P. are a,b,c respectively, then the sum of the A.P. is

If the first, second and the last terms of an A.P. are a,b,c respectively, then the sum of the A.P. is

The sum of the third and seventh terms of an A.P is 6 and their product is 8 find the sum of first sixteen terms of the A.P.

The first term and last term of an A.P. are respectively 1 and 157. If the sum is 3160 find the number of terms.

The sum of the first p terms of an A.P. is q and the sum of the first q terms of the same A.P. is p. Find the sum of the first (p+q) terms of the A.P.