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Person A and Person B have the exact same wardrobe which consists of 2 different pairs of shoes, 3 different pans, and 4 differnt shirts. What is the probability that Person A and Person B wear the same outfit?

 

I did it by doing: Person A can choose whatever they want to wear, it doesn't matter. The only thing that matters is that after person A chooses their outfit, Person B must choose the same outfit as person A. Therefore, person B has a 1/2*1/3*1/4 = 1/24 chance of choosing the same outfit as person A, and they have a 1/24 chance of wearing the same outfit.

 

My teacher did it by saying that person A has a 1/24 chance of choosing the same outfit as person B, and then person B had a 1/24 chance of choosing the same outfit as person A, so the answer was therefore 1/576.

 

Which one of us is right and why? (About half of my class did it the same way I did and our teacher is known for being wrong a lot and being scatterminded, so I just wanted to make sure I know which way is correct so I don't fail the big test at the end of the year.)

 May 10, 2016
 #1
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I believe your way is correct.

Even if your teachers way had merit it would be addition not multiplication.

But your way is correct otherwise you'd be double counting :) 

 May 10, 2016
 #2
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1/24 is the correct answer.

Be aware though, that if your teacher is marking the test, you need to be able to calculate the wrong answer, (else otherwise your correct answer will be marked wrong).

 May 10, 2016

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