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) A number 15 is divided into three parts which are in AP and sum of their squares is 83. The smallest part is

3) If the third term of an AP is 12 and the seventh term is 24, then the 10th term is

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

5) Common difference of sequence 5,8,11,14,… is