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Points A, B, C, and D lie on a line such that AB = 4AD = 9BC.  A point is selected at random between A and B. What is the probability that it is between C and D?

 

 Dec 7, 2020
 #1
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AB= 4AD  = 9BC

 

AB/ 4   = AD

 

AB/ 9 = BC

 

So

 

AB/4  +   AB/9  =    AD  +   BC

 

[ 13/36]AB =  AD + BC

 

So 

CD =  AB- [13/36]AB  =    23/36   AB

 

So....the probabi;ity is    23/36

 

 

cool cool cool

 Dec 7, 2020

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