P and Q walk around a circular track

P and Q walk around a circular track. They start at 7 a.m from the same point in the opposite directions. P and Q walk at a speed of 4 rounds per hour and 7 rounds per hour respectively. How many times shall they cross each other before 10 a.m

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #84962