GMAT Prep2 problem- help please

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GMAT Prep2 problem- help please

by jaydeer44 » Mon Aug 25, 2008 7:48 pm
how do I approach this problem? The answer is D.
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Re: GMAT Prep2 problem- help please

by sudhir3127 » Mon Aug 25, 2008 8:12 pm
jaydeer44 wrote:how do I approach this problem? The answer is D.
1/3 for me ..

here it goes...

assuming that 1 letter will be put into the envelope with its correct address

probability of first letter in correct envelope is 1/4
probability of second letter in wrong envelope is 1=1/3 = 2/3
probability of 3rd letter in wrong envelope is 1-1/2 = 1/2
4th letter in wrong envelope is 1

total is 1/4*2/3*1/2*1= 1/12

Since we will have 4 such combinations . total probability is

4/12 = 1/3

hope that helps

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by jaydeer44 » Tue Aug 26, 2008 8:10 am
great, thanks!