Number Series Puzzles - 16

1. What number should replace the question mark to definite rule number ?
  
     147,159,174,186,?

A:- 201

      147
      147+12(1+4+7) = 159
      159+15(1+5+9) = 174
      174+12(1+7+4) = 186
      186+15(1+8+6) = 201.

2.  What comes next in this series : 1,7,8,15,23,38,61,?

A:-  99
     
       1,7 
       1+7 = 8
       8+7 = 15
       15+8 = 23
       23+15 = 38
       38+23 = 61
       61+38 = 99.

3.  What number shoul replace the question mark ?

     52,25,77,77,?,451,605

A:-  154

       52,25  (reverse order)
       52+25 = 77
       77,77  (reverse)
       77+77 = 154
       154,451  (reverse)
        154+451 = 605  .

4.  What number should replace the question mark ?

     100,99.5,98,95.5,92,87.5,?

A:-  82

        100
        100-0.5 = 99.5
        99.5-1.5 = 98
        98-2.5 = 95.5
        95.5-3.5 = 92
        92-4.5 = 87.5
        87.5-5.5 = 82.