How to get the answer right: - Count how many drum sound you hear after the thunder; - Math: rbh(c * 343) = a - c = count - a = answer - rbh = round by hundreds - Now answer.
This is the "meter-distance" calculation method. for the mile one, divide by 5, but do not do this here, it will be wrong. This works in real life. Apply when stormy nights, becaus at night is better to see the thunders. Count the strong lightings!