Remark
I didn't know this was a calculus question. How dumb of me.
f(x + h) - f(x)
==========
x + h - h
50/6 - 51/6 =( -1/6+ h)/h
The h's will disappear when the limit is taken.
answer - 1/6 which is A. If anyone else answers take their answer.
I would advise you to use the website desmos
I don’t think this question can be solved without the measurements of the box. If you could re-upload this question with a picture of the box or with the measurements that would be great :)
your answer would be A. 122/27