## Precalculus (6th Edition) Blitzer

The probability that a student is not from a high income family is $\frac{6}{7}$
We know that the total number of students is 350. Therefore, $n\left( S \right)=350$ Also, the number of students from a high income family is $50$ Therefore $n\left( E \right)=50$ The probability of students from a high income family is given below: \begin{align} & \text{P}\left( \text{high} \right)=\frac{\left( \begin{align} & \text{Total number of students having } \\ & \text{ high income parents} \\ \end{align} \right)}{\text{Total number of students}} \\ & =\frac{50}{350} \\ & =\frac{1}{7} \end{align} And the probability of students who are not from a high income family is given below, \begin{align} & \text{P}\left( \text{not high} \right)=1-\text{P}\left( \text{high} \right) \\ & =1-\frac{1}{7} \\ & =\frac{6}{7} \end{align} Thus, the probability that a student is not from a high income family is $\frac{6}{7}$.