Solution: The model states that each hour the count is multiplied by 3. After 1 hour: $ 3^1 $, after 2 hours: $ 3^2 $, so after 4 hours: $ 3^4 $. But the problem states the population is $ 3^6 $ times initial, which contradicts unless growth rate differs. However, assuming the model is correct, after 4 hours: - go-checkin.com