The expected value of a random variable can be calculated by:
![E\lbrack X]=\sum_{i\mathop{=}1}^nx_i\cdot Pr(X=x_i)](https://img.qammunity.org/2023/formulas/mathematics/college/e0gl3afl25449hmxm0z62pmuy7fpbqs01e.png)
Where Pr(X = x_i) is the associated probability for the value x_i. Using the values from the table, we calculate the expectation value for the money a newly recruited customer can generate:
![\begin{gathered} E\lbrack X]=0.4\cdot0+0.1\cdot10+0.2\cdot40+0.3\cdot100 \\ \\ \Rightarrow E\lbrack X]=\$39 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/goepehv7jd3wgb6rigciffj9xdzfiextoi.png)
A newly recruited customer can be expected to generate $39.
Since the recruitment costs $50, it is not worth attempting to recruit new customers.