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Hey guys, new to the forum here, I hope to ask a lot of questions and also answer many questions that may fall into my strengths.
I have a supposedly easy combination question:
3 cards are drawn at random from a deck of 52 cards WITH replacement. How many ways can I get exactly 2 hearts?
Or think of it this way: 2 of the 3 cards should be hearts. This can happen in 3 ways (i.e. 3C2): HHO, HOH, OHH fluke has already explained that the probability of picking a Heart is 1/4 and of some other card is 3/4
P.S.: Don't waste too much time on this. GMAT will ask only limited question from this type (maybe around 2). Better delve into it if you are through with other relatively easier topics with greater weight, such as inequality, ratio, percentage, sets, statistics. _________________
13- Number of ways you can pick hearts 39- Number of ways you can pick others \(C^3_2\)- Number of ways to select the position of the 2 hearts out of 3
Dear Fluke & karishma
do we really need to multiply \(C^3_2\) to \((13)^2*39\) as in selection order dosent matter at all all we need to ensure is that there should be two hearts and one any other cards thats it
according to my knowledge answer should be \((13)^2*C^3_1^9\) please clarify
Say you pick out a card from the deck and it is the 3 of Hearts. You return the card back. Then you pick out another one and it is the 4 of Hearts. You return it again. Then you pick out another card and that is the 5 of Spades. Now imagine another situation. You pick out the first card and it is the 5 of Spades. You return it to the deck. You pick out another card and that is the 3 of Hearts. You put it back. Then you pick out another card and that is the 4 of Hearts. Tell me, are the two cases the same? Isn't there a sequence involved? If you want to find the number of ways in which you can get the 3 of Hearts, the 4 of Hearts and the 5 of Spades, wouldn't you add these two cases? _________________
Check out this awesome article about Anderson on Poets Quants, http://poetsandquants.com/2015/01/02/uclas-anderson-school-morphs-into-a-friendly-tech-hub/ . Anderson is a great place! Sorry for the lack of updates recently. I...