Because the frictional force between the orange skin peel is great enough when you are walking for it to be carried on the tray, along with the gravitational force downwards onto the tray. When you stop, the force that you exerted moving forward it the same as on the tray and on the orange. So when you stop, the force is still on the orange as the same velocity as your we’re traveling, while the tray and you stop.
The force depends on the mass of both objects and the distance between them
F = G*m1*m2/r^2
So the force has a linear connection with the mass of both objects and a quadratic connection with the distance between the center of masses
Devon will travel 180m in 12 seconds. All you have to do is multiply 15 by 12. Hope this helps