Precalculus (6th Edition) Blitzer

The probability that a randomly selected student attends a private college among people from a middle-income family is $\frac{5}{16}$.
The probability that a student attends private college from a middle income family is: \begin{align} & \text{P}\left( \text{private college, middle income family} \right)\text{ = }\frac{\text{students attend priavate college}}{\text{students from middle-income family}} \\ & =\frac{50}{160} \\ & =\frac{5}{16} \end{align}