1. **State the problem:** We are given the equation $y = ax$ and the value $y = 30$ when $c = 50$. We need to find the relation between $y$ and $x$. 2. **Analyze the given information:** The equation $y = ax$ suggests $y$ is proportional to $x$ with proportionality constant $a$. 3. **Clarify the role of $c$:** Since $c$ is given as 50 but not directly in the equation, we assume $a$ depends on $c$, so $a = f(c)$. 4. **Express $a$ in terms of $c$:** If $a$ depends on $c$, and at $c=50$, $y=30$, then $30 = a(50) imes x$. 5. **Find the relation:** Without $x$ value, we cannot find $a$ numerically. But the relation remains $y = a(c) x$. 6. **Conclusion:** The relation between $y$ and $x$ is $y = a x$, where $a$ may depend on $c$. Given $y=30$ when $c=50$, the exact relation requires more information about $x$ or $a$. **Final relation:** $$y = a x$$ where $a$ is a constant or function of $c$.