There are 3 doors to a lecture room. In how many ways can a lecturer enter the room from one door and leave from another door?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
2 (6)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
As the lecturer can't leave the hall by the door he/she enters.
So, number of ways can a student enter the hall through a door and leave the hall by a different door is = 3 × 2 = 6
