For a recent 41-year period, there were 5,469 major earthquakes; these are earthquakes
measuring at least 6.0 on the richter scale in the world (based on u. s. geological survey
data).
a

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?