Problem: To m ounces of an m% solution of acid, x ounces of water are added to yield an (m−10)% solution. If m>25, then x is:
Answer Choices:
A. m−1010 m
B. m−105m
C. m−10m
D. m−205m
E. not determined by the given information
Solution:
m+xm⋅100m=100m−10∴x=m−1010m. The solution is valid for m>10. It, therefore, holds for m>25.