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Hi Kate. The way I read this is that the toad starts below step #1 and each time he moves between two steps (either going up or going down) is a jump. On the first jump, the toad reaches the 2nd step. ... On the fifteenth jump, the toad reaches the 9th step. So you are right: 17 jumps. Think of it as two interwoven sequences: Odd numbered jumps end on floors 2, 3, 4, 5, 6, 7, 8, 9, 10 So the mixed sequence is 2, 1, 3, 2, 4, 3, 5, 4, 6, 5, 7, 6, 8, 7, 9, 8, 10. Cheers,  


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