If the sum of 8 terms of an A.P. is 64 and the sum of 19 terms is 361, find the sum of n terms.

The sum of 8 terms of an A.P. is 64 and sum of 17 terms is 289. Find the sum of its 'n' terms.

The sum of 8 terms of an A.P. is -64 and sum of 17 terms is 289. Find the sum of its 'n' terms.

If the sum of 7 terms of an A.P. is 49 and that of 17 terms is 289, find the sum of n terms.

If the sum of p terms of an A.P. is q and the sum of q terms is p, then the sum of p+q terms will be

If the sum of p terms of an A.P. is q and the sum of q terms is p , then the sum of the p+q terms will be

If the sum of p terms of an A.P. is q and the sum of q terms is p, then the sum of p+q terms will be

If the sum of first 7 terms of an A.P. is 49 and that of 17 terms is 289, find the sum of first n terms.

If the sum of first 7 terms of an A.P is 49 and that of 17 terms is 289, find the sum of first n terms.

If the sum of first 7 terms of an A.P. is 49 and that of its 17 terms is 289, find the sum of first n terms of the A.P.

If 10th term of an A.P is 13, then the sum of 19 terms =