document.write( "Question 1120568: Three digit numbers are formed from 5 cards labelled 1,2,3,4 and 5.
\n" ); document.write( "A) how many different 3-digit numbers can be formed?
\n" ); document.write( "B) if one of these numbers is selected at random what is the probability
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\n" ); document.write( "C) how many of these 3-digit numbers are even?
\n" ); document.write( "D) what is the probability of randomly selecting a 3- digit number less than
\n" ); document.write( " 500 with its digits arranged in descending order \n" ); document.write( "
Algebra.Com's Answer #736733 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
Three digit numbers are formed from 5 cards labelled 1,2,3,4 and 5.
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\n" ); document.write( "A) how many different 3-digit numbers can be formed?
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document.write( "Choose the first digit any of the 5 ways.\r\n" );
document.write( "Choose the second digit any of the 4 remaining unchosen digits.\r\n" );
document.write( "Choose the third digit any of the 3 remaining unchosen digits.\r\n" );
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document.write( "Answer: 5P3 = 5∙4∙3 = 60\r\n" );
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\n" ); document.write( "B) if one of these numbers is selected at random what is the probability
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document.write( "Choose the third digit any of 3 ways (1,3 or 5)\r\n" );
document.write( "Choose the first digit any of the 4 remaining unchosen digits.\r\n" );
document.write( "Choose the third digit any of the 3 remaining unchosen digits.\r\n" );
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document.write( "Number of different odd 3-digit numbers = 3∙4∙3 = 36 ways. \r\n" );
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document.write( "Probability of odd 3-digit number = 36/60 = 3/5\r\n" );
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\n" ); document.write( "C) how many of these 3-digit numbers are even?
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document.write( "Easy way (using B):  1 - 3/5 = 5/5 - 3/5 = 2/5\r\n" );
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document.write( "Or From scratch (without using B):\r\n" );
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document.write( "Choose the third digit any of 2 ways (2 or 4)\r\n" );
document.write( "Choose the first digit any of the 4 remaining unchosen digits.\r\n" );
document.write( "Choose the third digit any of the 3 remaining unchosen digits.\r\n" );
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document.write( "Number of different even 3-digit numbers = 2∙4∙3 = 24 ways. \r\n" );
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document.write( "Probability of even 3-digit number = 24/60 = 2/5\r\n" );
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\n" ); document.write( "D) what is the probability of randomly selecting a 3- digit number less than
\n" ); document.write( " 500 with its digits arranged in descending order
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document.write( "Consider the 4-digit number with its digits arranged in descending\r\n" );
document.write( "order:  4321\r\n" );
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document.write( "If we remove any one of those 4 digits from 4321 the remaining 3 will form a\r\n" );
document.write( "number less than 500 with digits in descending order.  That's 4 digits\r\n" );
document.write( "choose 1 to remove, or 4C1 = 4 ways.\r\n" );
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document.write( "Probability of a 3-digit number less than 500 with its digits arranged in\r\n" );
document.write( "descending order = 4/60 = 1/15.\r\n" );
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document.write( "Edwin
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