To find the monthly decrease in the car's value when it decreases by $2,500 over 6 months, you can use division of rational numbers.
The formula to find the monthly decrease is:
\[ \text{Monthly Decrease} = \frac{\text{Total Decrease}}{\text{Number of Months}} \]
In this case:
\[ \text{Monthly Decrease} = \frac{2500}{6} \]
Now, let's perform the division:
\[ \frac{2500}{6} \approx 416.6667 \]
Now, rounding to the nearest hundredth:
\[ 416.67 \]
Thus, the value of the car decreases by approximately $416.67 per month.