What's a problem to your math
Answer:
C
Step-by-step explanation:
I explained in my last answer but someone deleted it
Set the equations equal to each other because you need to find when they will be the same.

Add 5x to each side and subtract 256 from each side to get the variable alone.

Divide by 2.
To find the percentage divide 10 by 100.. each chapter would make up 10% of the book.