Selection of terms in an AP

If 2 and 31 appear as two terms in an AP,then which is in correct (A) common difference of the AP is a rational number (B) all the terms of the AP must be rational (C) all the terms of the AP must be integer (D) all the terms of the number of terms of the AP must be rational

In an A.P,the sum of m terms of an AP is n and sum of n terms of AP is m,then prove that sum of (m+n) terms of AP is-(m+n)

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.:

Suppose that the first and the 5^(th) terms of an A.P. are-14 and 2 respectively If the sum of the terms of the A.P is 40, find the number of terms in the A.P.

In an A.P.the sum of m terms of an AP is n and sum of n terms of AP is m,then prove that sum of (m+n) terms of AP is -(m+n)

If the sum of 4 terms of an AP is 36, then AM of the AP is:

If 6 times of 6th term of an A.P. is equal to 7 times term, then the 13th term of the A.P. is