Question 432084
It is possible to estimate how far away a bolt of lightning is by counting the seconds between the flash and the thunder.
 If we let the variable s represent the number of seconds, then a bolt of 
lighting is approximately miles away.
:
Use 1100 ft/sec for the speed of sound
;
a. A lifeguard sees a flash of lightning.
 After 20 seconds, she hears thunder. About far away was the lightning?
d = {{{(1100 * 20)/5280}}}
d = 4.167 miles away
:
:
b. A golfer sees a bolt of lightning strike a tree a few holes away.
 He hears the thunder for about 2.5 seconds later.
 About how far away from the tree is he standing?
d = 2.5 * 1100
d = 2,750 ft away