解答上面的数学题---Here is the extracted content from the image: **Question Stem:** 某海港南北方向上有两个海岸观测站A, B，距离为10海里，从港口出发的一艘轮船正沿北偏东30°方向匀速航行，某一时刻在观测站A, B两处分别测得此轮船正好航行到南偏东30°和北偏东75°方向上的C处，经过0.5时轮船航行到D处，此时在观测站A处测得轮船在北偏东75°方向上，求轮船航行的速度。(结果精确到0.1海里/时，参考数据：$\sqrt{2} \approx 1.414, \sqrt{3} \approx 1.732$) **Other Relevant Text:** * **Precision Requirement:** 结果精确到0.1海里/时 (Result accurate to 0.1 nautical miles/hour) * **Reference Data:** $\sqrt{2} \approx 1.414, \sqrt{3} \approx 1.732$ **Chart/Diagram Description:** * **Type:** Geometric/Navigation Diagram. * **Main Elements:** * **Points:** Four labeled points: A, B, C, D. * **Lines:** * A vertical line passes through points A and B, representing the North-South direction. Point B is below point A. The segment AB represents the distance between the two observation stations. An upward arrow near A indicates the North direction. * A line segment connects A and C (AC). * A line segment connects B and C (BC). * A line segment connects C and D (CD). This represents the path of the ship from C to D. * A line segment connects A and D (AD). * Another vertical line passes through point C, also with an upward arrow labeled "北" (North), indicating the North direction from C. * **Angles and Labels:** * At point A: The angle between the North direction (upward from A) and the line AD is 75°. The angle between the South direction (downward from A) and the line AC is 30°. * At point B: The angle between the North direction (upward from B) and the line BC is 75°. * At point C: The angle between the North direction (upward from C) and the line CD is 30°. * **Relative Position and Direction:** * A and B are on a North-South line, with B to the South of A. * The ship's path from C to D is in the North-East 30° direction. * From observation station A, point C is in the South-East 30° direction. * From observation station B, point C is in the North-East 75° direction. * From observation station A, point D is in the North-East 75° direction.