🔍 Key Concepts

• Latitude/longitude to distance on a Mercator chart • Formula: Speed = Distance / Time • Using the fact that 1 minute of latitude ≈ 1 nautical mile

💭 Think About

• How many minutes of latitude and longitude did you change between the two positions, and which component mainly affects distance on most exam problems? • Once you find the distance in nautical miles, what is the elapsed time in hours between 1919 and 1950? • After you compute Speed = Distance / Time, which answer choice is closest to your result?

✅ Before You Answer

• Be sure you converted the time difference into hours, not minutes. • Check that you measured or computed distance in nautical miles, not in minutes of arc or degrees. • Confirm whether the change in longitude significantly affects distance at this latitude, or if you can focus on the north–south (latitude) change for this type of problem.