The sound travels in an average speed of 340ms the lightning

The sound travels in an average speed of 340m/s the lightning that comes from a cloud caused by a storm, is obseved almost inmediately. If th sound of lightning comes to our ears about 1.3 minutes after. How far is the storm?

Solution

1.3 minutes = 78 seconds
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That gives you 340 m/sec and 78 seconds.
Take it from there.