Second thirty first and last terms of an A.P. are (31)/4,1/2` and `-(13)/2` respectively. Find the number of terms in the A.P.

The 2nd, 31st and last terms of an A.P. are 7 3/4, 1/2 and -6 1/2 respectively, find the first term and the number of terms.

If the 5th and 12th terms of an A.P. are 30 and 65 respectively, what is the sum of the first 20 terms ?

If 7th and 13th terms of an A.P. be 34 and 64 respectively, then its 18th term is:

If the 3rd and 9^(th) terms of an A.P. are 4 and - 8 respectively, which term of this A.P. is zero.

The first and last terms of an A.P. are a and l respectively. Show that the sum of nth term from the beginning and nth term from the end is a + l.

How many terms are there in A.P. whose first and fifth terms are -14 and 2 respectively and the sum of terms is 40 ?

First , second and middle terms of an A.P. are a,b,c respectively . The sum of AP is :

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

The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.