A boat is situated between a lighthouse and a ship such that all three of them are in a straight line. If the angles of depression of the boat and the ship from the top of the lighthouse $20$ meters above sea level are $30$ degrees and $15$ degrees respectively. What is the distance between the boat and ship?
I did $20\tan(75^\circ) - 20\tan(60^\circ)$ which gave me $40$ meters and I am not sure if it's correct since the instructions said round your answer in hundredths.