Hopping Rabbit
A rabbit hops up a 7-step staircase. In each hop the rabbit can climb either 1 or 2 steps. What is the number of different ways in which the rabbit can go upstairs ? (the order of hops matters , e.g. a 1-step hop followed by a 2-step hop is considered different from the same hops in reverse order)
The answer is 21.
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1 solution
As the rabbit can hop 1 step or 2 steps so the maximum no of jumps will be 7 jumps(all single hops) and a minimum of 4 jumps (3 double hops and one single hop). We also have cases of 5 and 6 jumps. For all single hops(7 jumps) we have a single combination for 6 jumps we have 6 combinations for 5 jumps we have 10 combinations and for 4 jumps we have 4 combinations which gives us a total of 21 combinations