The officer is eligible for a 20% discount, so the discounted price would be $85 - (20% of $85) = $85 - ($85 * 0.20) = $85 - $17 = $68.
Then, the officer is eligible for an additional 25% off the discounted price, so the final price would be $68 - (25% of $68) = $68 - ($68 * 0.25) = $68 - $17 = $51.
The final price the officer has to pay for duty shoes is $51.
#### 51
The answer is: 51
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
What is the final price an officer who has served at least three years has to pay for duty shoes, if the original price is $85 and they are eligible for a 20% discount and an additional 25% off the discounted price?

### Answer:
