A cliff diver leaps from a 100-foot cliff into the Pacific. The diver’s height above the water is modeled by the functionP(x) = –16x 2 + 10x + 100, where x is time in seconds.During which interval is the diver at least halfway down?

Halfway down means the diver has fallen 50 feet, so the diver is 50 feet above the water. Set P(x) = 50: −16x² + 10x + 100 = 50, which gives a positive solution of about 2.1 seconds. The diver reaches the water when P(x) = 0, at about 2.8 seconds. Thus, the diver is at least halfway down from about 2.1 to 2.8 seconds, matching choice B, “2.1 < x < 2.8 seconds.”

AI-written and checked against the verified answer.