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A box contains 10 pairs of shoes (20 shoes in total). If two

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FarhinR
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Re: A box contains 10 pairs of shoes (20 shoes in total). If two [#permalink] New post   08 Aug 2023, 23:06
Total = 20
Pair = 10
For the first pick, I can pick any shoe out of 20 = 20/20
However, for the second pick I have to chose the one shoe from the pair.
Therefore 2nd pick = 1/19

1/20 * 1/19 = 1/19

The answer is C.

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Riya1475828
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Re: A box contains 10 pairs of shoes (20 shoes in total). If two [#permalink] New post   18 Mar 2024, 14:00
­Here's my way of solving this problem: 

Probability = No. of favorable outcome/Total no of outcome

Favorable outcome (Selecting matching pairs of shoes) = 20*1 (because there are 20 shoes to select from and 1 because each shoe will only have one other pair)
Total outcome (Selecting any shoe) = 20*19 (because there are 20 shoes to select from and 19 other shoes remaining for the second pick)

Probability of selecting matching pairs of shoes = 20/(20*19) = 1/19

Option C

Let me know if this helps! 
 
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nisheshj
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Re: A box contains 10 pairs of shoes (20 shoes in total). If two [#permalink] New post   26 Apr 2024, 11:04
tejal777 wrote:
A box contains 10 pairs of shoes (20 shoes in total). If two shoes are selected at random, what it is the probability that they are matching shoes?

A. 1/190
B. 1/20
C. 1/19
D. 1/10
E. 1/9

 

There are basically 10 pairs, and we need to pick a pair of shoes, why is the answer simply not 1/10?
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gmatclubot
Re: A box contains 10 pairs of shoes (20 shoes in total). If two [#permalink]
26 Apr 2024, 11:04
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