document.write( "Question 1153867: There are 10 pcs of fruit, 6 were pears. If worker randomly selects 3 pcs for a basket, what is the probability that all were pears? \n" ); document.write( "

Algebra.Com's Answer #776197 by ikleyn(52817) $\"\"$ $\"About$

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document.write( "There are two ways to solve this problem.\r\n" );
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document.write( "One way is to use the formula  P = .      (1)\r\n" );
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document.write( "The denominator of this formula,  ,  is the number of combinations of 10 items taken 3 at a time.\r\n" );
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document.write( "In other words, it is the number of all triples that can be formed from 10 pieces of fruits.\r\n" );
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document.write( "The numerator,  ,  is the number of all triples of pears that can be formed of 6 pears.\r\n" );
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document.write( " =  = 120.\r\n" );
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document.write( " =  = 20.\r\n" );
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document.write( "Therefore, the probability under the question is  P =  = .\r\n" );
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document.write( "Another way is to write\r\n" );
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document.write( "    P =  = simplifying =  =  = ,    (2)\r\n" );
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document.write( "which leads to the same answer.\r\n" );
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document.write( "In formula (2),  first factor    is the probability to get one pear from 10 fruits; \r\n" );
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document.write( "the factor    is the probability to get second pear from the remaining 9 fruits; \r\n" );
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document.write( "and the last factor    is the probability to get third pear from the remaining 8 fruits;.\r\n" );
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\n" ); document.write( "\n" ); document.write( "So, the problem can be solved by any of these two ways, and you should know both.\r
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