First, Second and last terms of a finite A.P. are m, n and 2m respectively, then sum of the series is

The first term and the last term of an A.P. are 2 and 29, respectively. If the sum of the series is 155, find the number of terms and common difference.

The first term and last term of an A.P. are 5 and 123 respectively. If the sum of the series is 3840, determine the number of terms and common difference.

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,band 2a , respectively, then its sum is

If the first,second and last term of an AP are a,b and 2a respectively,its sum 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

If first term, second term and last term of an A.P are a,b and 2a respectively then there sum is……