Using the 7:10 Rule of Thumb, how long will it take an exposure rate of 1,000 R/hr, measured l-hour after detonation

Question

Question: Using the 7:10 Rule of Thumb, how long will it take an exposure rate of 1,000 R/hr, measured l-hour after detonation, to decrease to 10 R/hr?

Options:

1.  7 hours
2.  10 hours
3.  49 hours
4.  100 hours

Answer 1

3. 49 hours

Using the 7:10 Rule of Thumb, it will take 49 hours for an exposure rate of 1,000 R/hr, measured l-hour after detonation, to decrease to 10 R/hr.