Answer
At $2000$ dollars in sales the earnings will be the same.
Work Step by Step
Let us assume that at $ x $ dollar in sales, the earnings are the same. Now, the equations for the two cases become:
1: $\$200$ and $5\%$ commission on sales,
$200+\frac{5x}{100}$
2: $15\%$ commission on sales,
$\frac{15x}{100}$
Then, for them to be the same we equate them:
$\begin{align}
& 200+\frac{5x}{100}=\frac{15x}{100} \\
& \frac{15x}{100}-\frac{5x}{100}=200 \\
& \frac{15x-5x}{100}=200 \\
& \frac{10x}{100}=200
\end{align}$
And simplify it further:
$\begin{align}
& x=200\cdot \left( \frac{100}{10} \right) \\
& x=2000
\end{align}$
Thus, the dollars of sales for which the earnings will be the same is $\$2000$.
