The Attempt at a Solution
The ball will have the same final velocity as Its initial. So, using the last equation 0=5+gt, where g is 10. Therefore, time to reach the maximum height is half seconds. To reach the same height it started from, kt will take another half a second, Totaltime is 1 second. So, its horizontal displacement is x=5(1)= 5m. Since the same time applies for the motion of the girl, she will have moved a distance of 3m. Is my reasoning correct?