Number Series Puzzles - 4

1.  What number continues the following sequence ?

     759,675,335,165,?

A:-  80

       75*9 = 675
       67*5 = 335
       33*5 = 165
       16*5 = 80

2.  What number should replace the qustion mark ?

     0,1,2,4,6,9,12,16,?

A:- 20

     0+1 = 1
     1+1 = 2
     2+2 = 4
     4+2 = 6
     6+3 = 9
     9+3 = 12
     12+4 = 16
     16+4 = 20

3. What numbers shoul replace the question marks ?

    0,1,3,6,7,9,12,13,15,18,?,?,?

A:-  19,21,24

       0+1 = 1
       1+2 = 3
       3+3 = 6

       6+1 = 7
       7+2 = 9
       9+3 = 12

      12+1 = 13
      13+2 = 15
      15+3 = 18

      18+1 = 19
      19+2 = 21
      21+3 = 24