Okay add 78 and 66. Then add 96 and 108. It should be 144 by 204. I know math is hard, but when you work at it you can do amazing things! I hope that helps you.
It likely hit a barrier like a wall for example and the force of the ball hitting the wall caused it to be pushed away. Another possibility is that the ball was kicked up some sort of slop and when it was at the ten feet it slowed down and then rolled back down. I hope this helps.
Answer:


Step-by-step explanation:
Since y=x+1 plug it into bottom equation as y.

Subtract 1 from both sides

Subtract 5x from both sides

Divide both sides by -4

Now x=-3 into the top equation to find y

y=-2
5 + 8s = 15 + 3s
8s - 3s = 15 - 5
5s = 10
s = 10/5
s = 2 <=== they will charge the same at 2 sq ft