Help again please ?? I have 5 more that needs to be answer also ..

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

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?

Ten times the square of a non-zero number is eqaul to ninety times the number