Number Series Puzzles - 10

1.  What number should replace the question mark ?

     1,5,11,19,29,?,55

A:-  41

       1
       1+4 = 5
       5+6 = 11
       11+8 = 19
       19+10 = 29
       29+12 = 41
       41+14 = 55.

2.  What number should replace the questiion mark ?

     6,10,18,34,?
 
A:-  66

        6
        6+4 = 10
        10+8 = 18
        18+16 = 34
        34+32 = 66.

3.  Look at this series : 1000,200,40,... What number should come next ?

A:-  8

       1000
       1000/5 = 200
       200/5 = 40
       40/5 = 8.

4.  Look at this series : 5.2,4.8,4.4,4,..... What number should come next ?

A:-  3.6

       5.2
       5.2-0.4 = 4.8
       4.8-0.4 = 4.4
       4.4-0.4 = 4
       4.0-0.4 = 3.6.

5. Look at this series : 2,6,18,54,......  What number should come next ?

A:-  162

        2
        2+4 = 6
        6+12 = 18
        18+36 = 54
        54+108 = 162.