A stone is thrown horizontally from the top of a building an intial speed of 25 m/se. The stone strikes the ground after covering a horizontal distance of 75m. How high is the building? (take g= 10 m/s^2)

According to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does maria's voyage take according to samir?