B and C walk around a circular track

B and C walk around a circular track. They start at 9 a.m from the same point in the opposite directions. B and C walk at a speed of 5 rounds per hour and 4 rounds per hour respectively. How many times shall they cross each other before 1 p.m

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #42562