Number Series Puzzles - 6

1.  Which number completes the puzzle ?

     5,7,11,13,17,?

A:-  19

        5
        5+2 = 7
        7+4 = 11
       11+2 = 13
       13+4 = 17
       17+2 = 19.

2.  Look at this series: 2,1,1/2,1/4,.... What number should come next ?

A:- 1/8

      2
      2/2 = 1
      1/2 = 1/2
      (1/2)/2 = 1/4
      (1/4)/2 = 1/8.

3.  Look at this series: 7,10,8,11,9,12,..... what number should come next ?

A:-  10

       7
       7+3 = 10
       10-2 = 8
       8+3 = 11
       11-2 = 9
       9+3 = 12
       12-2 = 10.

4.  Look at this series: 36,34,30,28,24,..... What number should come next ?

A:- 22

     36
     36-2 = 34
     34-4 = 30
     30-2 = 28
     28-4 = 24
    24-2 = 22.