You are watching a lightning storm through your window. You see a big flash of light and you start counting the seconds: one potato, two potatoes, three potatoes... You hear loud thunder when you are at 13 in your counting. If sound travels one kilometer in three seconds, then how far is the storm from you?
You can get a pretty good approximation of the distance in miles, if you assume that sound travels one mile in five seconds. What is the approximate distance of the storm in miles? (You enter the unit of mile as "mi" without the quotation signs.)