You are enroute to assist vessel A. Vessel A is underway at 4.5 knots on course 233°T, and bears 264°T, 68 miles from you. What is the time to intercept if you make 13 Knots?

Correct Answer: Option D — 7h 37m

Using the relative motion vector triangle, the target's relative speed and direction are determined. By solving the triangle with the target's course/speed and your own speed, the closing speed is calculated. Dividing the range of 68 miles by the closing speed yields a time of 7 hours 37 minutes.