You see lightning and 30 seconds later you hear thunder. how far away is the thunderstorm? take the speed of sound to be 339 m/s. g

Let the observer be 'd' distance away from the thunderstorm and let light take 't' time to reach the observer

Since the speed of sound and light remains constant in a particular medium, we can use

Speed = Distance/Time

For light,

3 x 10^8 = d/t

t = d / (3 x 10^8) - 1

For sound,

339 = d / (t + 30) - 2

Putting value from 1 in 2.

d = 10^4 m (approx)