To find the ratio of chicken wings to sandwiches, we need to compare the number of chicken wings to the number of sandwiches.
Denise is making:
- 25 chicken wings
- 40 sandwiches
The ratio of chicken wings to sandwiches can be expressed as:
\[ \text{Ratio} = \frac{\text{number of chicken wings}}{\text{number of sandwiches}} = \frac{25}{40} \]
Next, we simplify the ratio \(\frac{25}{40}\) by finding the greatest common divisor (GCD) of 25 and 40, which is 5.
Now we divide both the numerator and the denominator by their GCD:
\[ \frac{25 \div 5}{40 \div 5} = \frac{5}{8} \]
Thus, the ratio of chicken wings to sandwiches in simplest terms is:
\[ \boxed{\frac{5}{8}} \]