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) 25 trees are planted in a straight line 5 metres apart from each other. To water them the gardener must bring water for each tree separately from a well 10 metres from the first tree in line with the trees. How far will he move in order to water all the trees beginning with the first if he starts from the well ?

3) 2,4,6,8,10,12,… is

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

5) An AP consist of 31 terms if its 16th term is m, then sum of all the terms of this AP is