number Series Puzzles - 5

1.  What numbers should replace the question marks ?

       1,4,9,16,25,?,?,?

A:-  36,49,64

       1*1 = 1
       2*2 = 4
       3*3 = 9
       4*4 = 16
       5*5 = 25
       6*6 = 36
       7*7 = 49
       8*8 = 64.

2.  What number should replace the question mark ?

      1,2,6,24,120,?

A:-  720

       1! = 1
       2! = 1*2 = 2
       3! = 1*2*3 = 6
       4! = 1*2*3*4 = 24
       5! = 1*2*3*4*5 = 120
       6! = 1*2*3*4*5*6 = 720.

3.  What should replace the question mark ?

      1,1,2,3,5,8,13,?

A:-  21

       1
       1
       1+1 = 2
       1+2 = 3
       2+3 = 5
       3+5 = 8
       5+8 = 13
       8+13 = 21.