Finding a Z-Score from Given Data

For a set of data, one data point with value 8.6 has a standard score or z-score of 1.5, while another data point from the same set with value 2.3 has a z-score of $-3$. What is the z-score of another data point from the same set with value 8.95? The answer is in the form $\frac{\alpha}{\beta}$ where $\alpha$ and $\beta$ are coprime positive integers. Input the value of $\alpha + \beta$.