While navigating in fog off a coastline of steep cliffs, you hear the echo of the ships fog horn 3 1/2 seconds after the signal was sounded. What is the distance to the shore?

Correct Answer: Option B — 640 yards

Sound travels approximately 1,100 feet per second in air. Multiplying 3.5 seconds by 1,100 feet gives 3,850 feet, which equals approximately 640 yards.