If you fly 15 minutes at 40 knots, how many nautical miles do you cover?

• A. 5 NM
• B. 10 NM
• C. 15 NM
• D. 20 NM

Answer: (B)

Distance traveled equals speed times time, with speed in knots meaning nautical miles per hour. At 40 knots you cover 40 nautical miles in one hour. Fifteen minutes is a quarter of an hour, so you cover a quarter of 40 nautical miles, which is 10 nautical miles. So you’d travel 10 NM.

If 5 NM were used, that would take about 7.5 minutes at 40 knots; 15 NM would take about 22.5 minutes; 20 NM would take 30 minutes.