Worked Probability Questions (2 of 3: Selecting sock pairs)

[沈博智-xy]

I like the way you used dominos to show the problem physically. I remember you teaching a similar style of question way earlier back, and i think this addition helps get a conceptual understanding of what's going on.

[paulw]

On the average, Nick will have a perfect sock week just about once every 18 years.

[wizix]

are the socks discarded out of the drawer every day? because if they are put into laundry end of every day, then the last day probability would depends on the days before it, even the second and third day will depend on the previous day.

[沈博智-xy]

The other way to think about f) is to say that on any given day, we want said day to have a day where they chose a non-matching pair. If we use analogy of pairs = same colour, then two colours have been chosen out of the five colours. There are only three colours left, so only a maximum of three pairs of socks can be made.

i.e. four pairs and one non pair is probability 0.

[Acharya_Slideshare]

Now this is mathmatication of my brain wow really enjoyed the question

[Ynook]

I am not sure if I got it. Each day is independent of each other, isn't it? On the first day, I have 10 options, on the second day I have 8 and so on. How can the probability be 1/9 for each? Why isn't it 1/9, then 1/7, then 1/5 and so on?
Of course, that's presuming the pair of the first sock I draw is still left in the drawer. If, for example, I draw blue and yellow on the first day, then if I draw yellow on the second day, the probability of making a pair is 0.
So, starting day 2, there should be two cases considered: one if the sock I draw first still has a pair left, one if the sock I draw has no more pair left.

Of course, in the real life, I can wear no socks if I don't draw a pair and I can keep my socks for the next day. If I don't draw a pair on the next day, I can pair them with what I got from the day before. This way it would make sense why the probability is 1/9, but that's not what we're calculating.

[janis]

Nick picks two socks every day. how can the chance be 1/9 on the third day? If he picked two different socks on the first day and two different socks on the second day there would be only 2 matching socks out of 6 left?

[kevinsessoms]

I really like this guy! He's really good at explaining math concepts. I do disagree with him on the fact that knowledge of the previous days choices do not affect the probability of the last day's choice. If you knew that the person chose perfectly matching colors on the previous 4 days then the probability is 100% that the last day the colors will match. There is not enough information to actually answer part of the question. There is also the probability that the previous 4 days the colors were not matching but 4 matching colors were used up leaving on one color.

[naveensingh]

may i request you to clarify, does Nick puts back the used socks in the same drawer?

[hanaelkamhawy]

ABC is a right-angled triangle at B where 3AC = 5BC, then tan A =3/4

Can someone please explain why tan A =3/4

[aussie]

ahh, but what if he put the dirty socks in the wash each day🧐🧐