How do you do this? So, I was doing a mini maths test and the question popped up. Because there were 4 kings, so I did 4/52(there were 52 cards) and then simplified it. I got it wrong. So confused! (No replacement, but it will be great if you guys show me with replacement as well).
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think about the multiplication rule. How many kings are there in a standard deck? – Samael Manasseh Dec 02 '20 at 07:08
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With or without replacement? – K.defaoite Dec 03 '20 at 01:12
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Hint: this can be solved using a “probability tree”
- start by drawing the first card. What are the odds of it being a king? Simply $4/52$.
- Now that you were lucky enough to draw the first king there are only ... kings left in the deck of only ... cards.
- Conclude.
b00n heT
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I will give another way to think about this problem, which might help the OP.
The sample space in this problem is ${52}\choose{2}$ since there are ${52}\choose{2}$ ways to pick a pair of cards. There are 4 kings, therefore there are ${4}\choose{2}$ ways of picking a pair of kings. From here we see that the probability of getting 2 kings is
$$P(\textrm{getting 2 kings }) = \frac{\textrm{number of ways the desired event can occur}}{\textrm{number of possible outcomes}}=\frac{{4}\choose{2}}{{52}\choose{2}}$$
Samael Manasseh
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it is not a division, it is "4 choose 2" which is the amount of way you can pick 2 thing from a group of 4. If you are not familiar with this concept you can read this: https://en.wikipedia.org/wiki/Combination#:~:text=Combinations%20refer%20to%20the%20combination,with%20repetition%20are%20often%20used. – Samael Manasseh Dec 02 '20 at 14:26