A Ball Is Thrown Straight Upward

Multiple Choice

A ball is thrown straight upward. Suppose that the height of the ball at time t is given by the formula h = - 18t ² + 126t, where h is in feet and t is in seconds, with t = 0 corresponding to the instant that the ball is first tossed. At what time(s) does the ball reach a height of 108 ft?

A) 1 sec, 6sec
B) 4 sec
C) 3 sec
D) 8 sec
E) 3 sec, 8sec