Number Series Puzzles - 15

1. What number shoul replace the question mark ?

   1,1,8,4,15,7,22,10,?

A:-  29

      1,1
      1+7 = 8
      1+3 = 4
      8+7 = 15
      4+3 = 7
      15+7 = 22
      7+3 = 10
      22+7 = 29.

2.  What two terms complete the series A  1  D  4  H  8  M  13  ?  ?

A:-  S 19

       A        D              H             M                    S
           B,C      E,F,G      I,J,K,L      N,O,P,Q,R
             2            3             4                    5

       1         4             8                     13                           19
           2,3      5,6,7       9,10,11,12        14,15,16,17,18
             2          3                4                            5

3.  What number should replace the question mark?

      1,2,6,12,36,72,?

A:-  216

       1
       1*2 = 2
       2*3 = 6
       6*2 = 12
       12*3 = 36
       36*2 = 72
       72*3 = 216.

4.  What numbers should replace the question mark ?

     15,30,45,90,135,270,?

A:-  405

        15
        15*2 = 30
        30*1.5 = 45
        45*2 = 90
        90*1.5 = 135
        135*2 = 270
        270*1.5 = 405.