Students in an Econometrics class recorded their income, x, and the total amount of money they spent, y, for one week (in dollars.) Based on these data, the linear regression line was calculated as: y^=51.24+0.871x.

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?