x < -6 means that x is lesser than -6. Thus, C and D are wrong. A filled up dot means that -6 is also a possible number for x, but here it says that x is lesser than -6, so it cannot be -6 itself. Thus, B with the filled up dot is also wrong.
The total time of flight of a projectile motion is calculated through the equation, t = 2v₀sinФ/g Substituting the known values, t = (2)(12 m/s)(sin 90)/9.8 m/s² t = 2.45 s Thus, the total flight time of the ball in the atmosphere is 2.45 s.