document.write( "Question 1105679: Postal codes in Canada have six characters, with the first, third, and fifth characters being letters, and the other characters being digits.\r
\n" ); document.write( "\n" ); document.write( "a)What is the maximum number of unique postal codes in Canada if the letters D, F, I, O, Q, and U are not used and neither W nor Z appears as a first character?
\n" ); document.write( "Answer: 18(10)(20)(10)(20)(10)= 7 200 000\r
\n" ); document.write( "\n" ); document.write( "b)How many of the postal codes described in part a) have the same letter repeated three times? \n" ); document.write( "

Algebra.Com's Answer #720610 by ikleyn(52781) $\"\"$ $\"About$

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\n" ); document.write( "Postal codes in Canada have six characters, with the first, third, and fifth characters being letters, and the other characters being digits.\r
\n" ); document.write( "\n" ); document.write( "a)What is the maximum number of unique postal codes in Canada if the letters D, F, I, O, Q, and U are not used and
\n" ); document.write( "neither W nor Z appears as a first character?
\n" ); document.write( "Answer: 18(10)(20)(10)(20)(10)= 7 200 000\r
\n" ); document.write( "\n" ); document.write( "b)How many of the postal codes described in part a) have the same letter repeated three times?
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\n" ); document.write( "\n" ); document.write( "The solution for the question a)\r
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document.write( "a)  1-st character can be any of (27-6-2) = 19 letters  - 19 opportunities.\r\n" );
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document.write( "b)  2-nd character can be any of 10 digits              - 10 opportunities.\r\n" );
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document.write( "c)  3-rd character can be any of (27-6) = 21 letters    - 21 opportunities.\r\n" );
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document.write( "d)  4-th character can be any of 10 digits              - 10 opportunities.\r\n" );
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document.write( "e)  5-th character can be any of (27-6) = 21 letters    - 21 opportunities.\r\n" );
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document.write( "f)  6-th character can be any of 10 digits              - 10 opportunities.\r\n" );
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document.write( "Answer to question a) is  19*10*21*10*21*10 = 8379000 possible codes.\r\n" );
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