boat is sailing due east parallel to the shoreline at a speed of 10 km/h. The captain spots a lighthouse on the shore at a bearing of is 30° S. After travelling for 15 minutes the captain remeasures the bearing and find it is E 32 S. Find the distance from the boat to the shore What assumptions are you making?
Draw a diagram. You can see that if the distance is x km, then
x cot30° - x cot32° = 10 * 15/60
I'll let you determine the several assumptions involved.