If your asking for what that would be called cause I don't understand what your asking but it would be called the midpoint
Per damaged carton the clerk uses 7 feet 7 inches of twine.
or
91 inched total.
multiply 91 times the amount of cartons needed (17) your answer is 1547
The square root of -56 is 7.4833 (feel free to round it up to 7.5)
I hope this helps you!
If it is only white and silver cars then it would me 75%