What is the value of $a$ if $(a, b)$ is the solution to the system $\left\{\begin{array}{l}y=2 \\ 5 x-y=93\end{array} ?\right.$

Step 1 ：We are given a system of two linear equations with two variables, $x$ and $y$. We are asked to find the value of $a$ if $(a, b)$ is the solution to the system. Since we are given that $y = 2$, we can substitute this value into the second equation to solve for $x$.

Step 2 ：Substitute $y = 2$ into the second equation: $5x - 2 = 93$

Step 3 ：Solve for $x$: $x = \frac{93 + 2}{5} = \frac{95}{5}$

Step 4 ：Calculate the value of $x$: $x = 19$

Step 5 ：Final Answer: The value of $a$ is \(\boxed{19}\)