A large number of samples of water were tested for the presence of two different minerals, $$X$$ and $$Y$$. Of all the samples tested, 52 percent showed the presence of $$X$$, 18 percent showed the presence of $$Y$$, and 10 percent showed the presence of both $$X$$ and $$Y$$.
Quantity A
The percent of all the samples tested that showed the presence of neither X nor Y