Find an A.P. in which the sum of any number of terms is always three times the squared number of these terms.

Find an A.P.in which the sum of any number of terms is always three xx the squared number of these terms.

Find an A.P whose sum of n terms is equal to three times the square of n.

If the sum of a certain number of terms of the A.P. 25,22,19........is 116 then find the number of terms.

Prove that the sum of an odd number of terms in A.P is equal to the middle term mutiplied by the number of terms

In an A.P. of 99 terms, the sum of all the odd-numbered terms is 2550. Then find the sum of all the 99 terms of the A.P.

In an A.P. of 99 terms, the sum of all the odd-numbered terms is 2550. Then find the sum of all the 99 terms of the A.P.

In an A.P. of 99 terms, the sum of all the odd-numbered terms is 2550. Then find the sum of all the 99 terms of the A.P.