Math
posted by Anonymous .
Gravity on the moon is about onesixth of gravity on Earth. An astronaut standing on a tower 20 feet above the moon's surface throws a ball upward with a velocity of 30 feet per second. The height of the ball at any time t (in seconds) is h(t) = 2.67t squared + 30t + 20. To the nearest tenth of a second, how long will it take for the ball to hit the ground.

h(t) will be zero at the ground
0=2.67t^2+30t+20
Use the quadratic equation.