Brianna has a pet bunny named Sir Fluffles. Sir Fluffles is capable of hopping up either one step or two at a time. How many different ways could Sir Fluffles ascent a flight of 6 stairs?
[Hint: Let S represent a single step and D represent a double step. SSSSD, SSDSS and DDD are three different 2
ways of hopping up the stairs]
