Item 17 To estimate how many miles you are from a thunderstorm, count the seconds between when you see lightning and when you hear thunder. Then divide by 5. Write and solve an equation to determine how many seconds $s$ you would count for a thunderstorm that is 2 miles away. Item 17 To estimate how many miles you are from a thunderstorm, count the seconds between when you see lightning and when you hear thunder. Then divide by 5. Write and solve an equation to determine how many seconds $s$ you would count for a thunderstorm that is 2 miles away.