마스터프렙 No.1 유학생 전문 인터넷 강의 사이트

COMMUNITY


Title	[Harim Yoo] The Essential Guide to Competition Math (Fundamentals): Topic 2, #15
	The Essential Guide to Competition Math (Fundamentals)		11
Author	alo***	Date Posted	2024-03-05 오후 3:30:25
Hi Mr. Yoo, Thank you so much for replying back in all my other posts, your explanations have really been helpful and cleared up a lot of foggy areas! Sorry, but I have another question... For Question #15 (last question in the video) of Topic 2 in video #11, could you please elaborate on how and why you multiplied 5!/2! to get the different combinations when the orders are switched? Is it because there are 5 cards and 2 indistinguishable cards? I'm not sure... Thank you so much for your time!
2024-03-07 오후 2:14:44 Here goes the answer to your question. Imagine we have {1,1,2,3,4} as shown in the lecture. In the very last step, we multiply by 5!/2! because two 1s are indistinguishable. Your logic is correct! Ask any other question, when you are taking lectures. Yay!