The sum of the first 51 terms of the arithmetic progression whose 2nd term is 2 and 4th term is 8, is ________.

The sum of first 5 terms of an arithmetic progression is 80,third term will be __

The sum of the first 20 terms of an arithmetic progression whose first term is 5 and common difference is 4, is __________.

What is the sum of the first 13 terms of an arithmetic progression, if the 5th term is 1 and the 8th term is - 17?

What is the sum of the first 9 terms of an arithmetic progression if the first term is 7 and the last term is 55?

What is the sum of the first 12 terms of an arithmetic progression, if the first term is 3 and the last term is 47?

Write the formula to find the sum of first n terms of an Arithmetic progression, whose first term is a and the last term is a_n .

Write the formula to find the sum of first n terms of an Arithmetic progression, whose first term is a and the last term is a_n .

Find the sum of the first 51 terms of the A.P.: whose second term is 2 and fourth term is 8.

Find the sum of the first 51 terms of the A.P.: whose second term is 2 and fourth term is 8.