Answer:
4 pm to 6 pm
Step-by-step explanation:
From 4 pm to 6 pm, the temperature dropped 8 degrees in 2 hours. That means that it should have dropped 4 degrees in 1 hour.
From 6 pm to 10 pm, the temperature dropped 9 degrees in 4 hours. That means it should have dropped 9/4 = 2.25 degrees in 1 hour
4 degrees is higher than 2.25 degrees, meaning that there was a higher temp drop from 4pm to 6pm
