Two balls A and B are thrown vertically upwards from the same location on the surface of the earth with velocities 2gR/3‾‾‾‾‾√ and 2gR/3‾‾‾‾‾‾√ respectively, where R is the radius of the earth and g is the acceleration due to gravity on the surface of the earth. The ratio of the maximum height attained by A to that attained by B is