It will take 38 seconds for the sound to reach you
Step-by-step explanation
Step 1
Let
speed of sound: 767.269
speed of ligth : 670616629 mph
also

Step 2
a)hear the thunder
let
distance =8.1 miles
time=t
speed = 767.269 mph
replace

Step 2
we have the time in hours, the question is asking for how many seconds, so we need to convert the hours into seconds

hence

therefore,the answer is
It will take 38 seconds for the sound to reach you
I hope this helps you