in a stair case there are 10 steps. a chjild can step in 1 or 2 at a time.wat are ways that a child can climb up?

• 1111111111-1way
  111111112-9c1
  11111122-8c2
  1111222-7c3
  112222-6c4
  22222-1
  total-89 ways
• 9 years agoHelpfull: Yes(31) No(0)
• 1111111111- 1 way
  111111112- 9!/(8!) ways=9 ways
  11111122- 8!/(6!*2!) ways= 28 ways
  1111222- 7!(4!*3!) ways= 35 ways
  112222- 6!/(2!*4!)= 15 ways
  22222- 1 way
  so total ways= 1+9+28+35+15+1=89 ways
  
• 9 years agoHelpfull: Yes(14) No(0)
• Ans is 89 .
  Let x be number of 2 steps x can be 0,1,2,3,4,5
  10c0+9c1+8c2+7c3+6c4+5c5=89.
• 9 years agoHelpfull: Yes(7) No(1)
• fibonacci series 1 2 3 5 8 13 21 34 55 89
• 9 years agoHelpfull: Yes(2) No(2)
• 
  y we havent taken the case 1212121
• 9 years agoHelpfull: Yes(1) No(2)
• 55 way
  10c1+10c2=55 way
• 9 years agoHelpfull: Yes(1) No(8)
• 5!/5!+6!/4!2!+7!/3!4!+8!/2!6!+9!/1!8!+10!/10!
  =1+15+35+28+9+1
  =89
• 9 years agoHelpfull: Yes(1) No(0)
• 89 ways.
  9+28+35+15+2
  
• 9 years agoHelpfull: Yes(1) No(0)
• 89
  10c0+9c1+8c2+7c3+6c4+5c5
  
• 9 years agoHelpfull: Yes(1) No(0)