1. The problem statement, all variables and given/known data A supersonic plane flies at Mach 3 at an altitude of 20,000 m. A person on the ground sees the plane directly overhead. How much time passes the before she hears the sonic boom? 2. Relevant equations f=fo(v+-vo/v-+vs) 3. The attempt at a solution I don't really know how to start up with this one, I was hoping for some help here.