emeraldcw

emeraldcw

New member
Joined
Dec 27, 2011
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1
what are the odds of 2 people picking the same card from a deck of 78 cards?
and how do i do this? thanx:p
 
Hello, emeraldcw!

I agree with Unknown008 . . . We need more information.

What is the probability of 2 people picking the same card from a deck of 78 cards?

I will take a calculated guess . . .

Since \(\displaystyle 78 \:=\:52 + 26\), I assume that half the cards are duplicated.

For example: all the red cards \(\displaystyle (\heartsuit,\:\diamondsuit)\) have duplicates;
. . . . . . . . . .the black cards \(\displaystyle (\spadesuit,\:\clubsuit)\) are normal.


The first person must draw a red card: .\(\displaystyle \dfrac{52}{78}\,=\,\dfrac{2}{3}\)

The second must draw its duplicate: .\(\displaystyle \dfrac{1}{77}\)


Therefore: .\(\displaystyle \text{Prob.} \:=\:\dfrac{2}{3}\cdot\dfrac{1}{77} \:=\:\dfrac{2}{231}\)
 
Or, 0 without replacement. The first card is gone. The second drawer can't draw it.
 
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