A man is walking along a numbered path

A man is walking along a numbered path. He repeats the following process of taking 10 steps forward and N steps backward. What should N be in order to guarantee at least one number along the path will be stepped on exactly 5 times. This includes a forward and backward step adding to the total. A tile must be stepped onto to count and not simply stepped off

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #44620