To find out how much money the salesperson had in sales last month, given that she earned $1,375 in commission and the commission rate is 5%, you can use the following formula:
\[ \text{Commission} = \text{Sales} \times \text{Commission Rate} \]
In this case, the commission earned is $1,375, and the commission rate is 5% (or 0.05 in decimal form).
You can rearrange the formula to solve for Sales:
\[ \text{Sales} = \frac{\text{Commission}}{\text{Commission Rate}} \]
Now plug in the values:
\[ \text{Sales} = \frac{1,375}{0.05} \]
Calculating that gives:
\[ \text{Sales} = 27,500 \]
Therefore, the salesperson had $27,500 in sales last month.