MathStudent1999
Junior Member
- Joined
- Mar 18, 2012
- Messages
- 76
Johnny got Christmas presents from each of his parents, each of his four grandparents, and one aunt and one uncle. He carefully wrote each thank you note, one to each of the donors, thanking each for the specific present they had sent to him. But then he asked his sister to address and mail the thank you notes, and she did not notice which note was intended for which relative. So she just addressed each of the eight envelopes to a different relative at random. What is the probability that exactly 5 of the 8 relatives got the notes that was intended for them? Express you answer as a common fraction.
I just did 1/8 * 1/7 * 1/6 * 1/5 * 1/4 * 2/3 * 1/2 * 1/1 and got 1/20160, but I'm not sure this answer is correct. Can someone check this problem and if this is wrong can someone teach me how to do this question?
I just did 1/8 * 1/7 * 1/6 * 1/5 * 1/4 * 2/3 * 1/2 * 1/1 and got 1/20160, but I'm not sure this answer is correct. Can someone check this problem and if this is wrong can someone teach me how to do this question?