Perguntas de entrevista de vagas de Graduate Trainee Software Engineer da empresa Rubykraft

Three people were trying to cross the bridge. Person A can cross the bridge in 10 minutes, Person B can cross the bridge in 5 minutes, Person C can cross the bridge in 2 minutes, and Person D can cross the bridge in 1 minute. It was heavily raining and they had only one umbrella. What's the minimum time required for all to cross the bridge without getting drenched?