Complex sentence: At full speed it took the "Carpathia" four hours to reach the "Titanic," while the "Titanic" only stayed afloat for two hours and sank before the "Carpathia" arrived.
Split into simpler sentences: At full speed it took the "Carpathia" four hours to reach the "Titanic," while the "Titanic" only stayed afloat for two hours. The "Titanic" sank before the "Carpathia" arrived.