The sum of the first four terms of an AP is 28 and sum of the first eight terms

The sum of the first four terms of an AP is 28 and sum of the first eight terms of the same AP is 88. Sum of first 16 terms of the AP is

2) Second term of sequence with general term n2 - 4/2 is

3) The sum of the first ten terms of an AP is four times the sum of the first five terms, then the ratio of the first term to the common difference is

4) The sum of 5 numbers in AP is 30 and sum of their squares is 220. Which of the following is the third term ?

5) 2,4,6,8,10,12,… is