At your current speed of 21 knots you only have enough fuel remaining to travel 404 miles. You must travel 731 miles to reach your destination. What should you reduce your speed (knots) to in order to reach your destination?

Correct Answer: Option C — 15.6

Navigational voyage optimization relies on the cubic fuel consumption law. Multiplying the current speed of 21 knots by the cube root of the ratio of remaining allowable distance (404 miles) to the required distance (731 miles) computes the adjusted speed of 15.6 knots.