A population of bacteria decreases from 10,000 to 8,000 in 3...

Question Analysis
This problem tests the understanding of calculating the decay rate in an exponential decay model.

Key Concept Explanation
The formula for exponential decay is , where is the amount after hours, is the initial amount, is the hourly decay rate, and is the time in hours.

Step-by-step Solution
1. Identify the given values: , , and .
2. Substitute these values into the formula: .
3. Divide both sides by 10,000: