pka
Elite Member
- Joined
- Jan 29, 2005
- Messages
- 11,971
You really ought to start a new tread with any new question.In how many ways can a 12 step staircase be climbed taking 1 step or 2steps at a time ?
Using only single steps there is only one way to reach the twelfth step.
Using only six double steps there is only one way to reach the twelfth step.
Now Using six single steps and three double steps how many ways are there to reach the twelfth step?
HINT: How many ways can one rearrange the string [imath]SSSSSSDDD~?[/imath]