Help me answer numbers 9-12. Please?

Which statement about perfect cubes is true

The means and mean absolute deviations of the individual times of members on two 4x400-meter relay track teams are shown in the table below. means and mean absolute deviations of individual times of members of 4x400-meter relay track teams team a team b mean 59.32 s 59.1 s mean absolute deviation 1.5 s 245 what percent of team b's mean absolute deviation is the difference in the means? 9% 15% 25% 65%

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab