Drawing the diagram helps. You must learn the extract the info from the question and translate it into the diagram so that you can find out what u are looking for. It's a skill that u must develop eventually. Practice more often and u should get a hang of such questions. I know it might be tough at the start, thats why we are here to help you. But please do not take our answers for granted hahaha, ultimately be familiar with the question type, and know the approach for solving this question. All the best! If have any questions do ask too :)