document.write( "Question 1182800: How many pairs (a,b) of positive integers are there such that a and b are factors of 6^6 and a is a factor of b? \n" ); document.write( "
Algebra.Com's Answer #812882 by ikleyn(52786)\"\" \"About 
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\n" ); document.write( "How many pairs (a,b) of positive integers are there such that \"a\" and \"b\" are factors of 6^6 and \"a\" is a factor of \"b\" ?
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\n" ); document.write( "\n" ); document.write( "            In this problem,  the terms  (the words)  \"factor\", \"factors\"  are used as synonyms of the term  \"divisor\", \r
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\n" ); document.write( "\n" ); document.write( "            It means that when the problem says  \"a\"  and  \"b\"  are factors of  \"6%5E6\",  it  DOES  NOT  necessary mean that   a*b = \"6%5E6\".\r
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\n" ); document.write( "\n" ); document.write( "            According to the context,  it  ONLY  MEANS  that  \"a\"  and  \"b\"  are the  DIVISORS  of  \"6%5E6\".\r
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\n" ); document.write( "\n" ); document.write( "            It is how I read,  understand,  interpret and solve this problem.\r
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document.write( "First of all,  \"6%5E6\" = \"%282%2A3%29%5E6\" = \"2%5E6%2A3%5E6\".\r\n" );
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document.write( "So, the divisors of the number  \"6%5E6\" = \"2%5E6%2A3%5E6\"  are all those and only those integer positive numbers  \"2%5Em%2A3%5En\",  \r\n" );
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document.write( "where  0 <= m <= 6,  0 <= n <= 6.\r\n" );
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document.write( "From this notice, it becomes clear that the total number of divisors  \" b \"  to the number  \"6%5E6\"  is  7*7 = 49.\r\n" );
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document.write( "    |    So, we solved part of the problem,  but not the whole problem,  yet.   |\r\n" );
document.write( "    |             Now I will analyse the remaining part.                        |\r\n" );
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document.write( "For any factor  \"a\"  of  b = \"2%5Em%2A3%5En%29\",  the \"a\"  has the form  a = \"2%5Ei%2A3%5Ej\",  where  0 <= i <= m,  0 <= j <= n.\r\n" );
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document.write( "It implies that for any of 49 factors  b = \"2%5Em%2A3%5En%29\",  there are  (m+1)*(n+1)  factors  \"a\"  to  \"b\".\r\n" );
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document.write( "Hence, when we calculate the number of pairs (a,b), as described in the problem, we sum up all these products (m+1)*(n+1) \r\n" );
document.write( "for all pairs  (m,n)  with m and n from 0 to 6 inclusive.\r\n" );
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document.write( "From this point, it is not difficult to get the idea that our sough number of pairs (a,b) is THIS PRODUCT\r\n" );
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document.write( "     (1 + 2 + 3 + . . . + 6 + 7)*(1 + 2 + 3 + . . . + 6 + 7).\r\n" );
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document.write( "Each factor in parentheses is the sum of the first 7 natural numbers  S = \"%287%2A8%29%2F2\" = 7*4 = 28.\r\n" );
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document.write( "Therefore, the answer to the problem's question is  \"there are  28*28 = 784  such pairs (a,b)\".\r\n" );
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document.write( "ANSWER.  There are 784 such pairs (a,b).\r\n" );
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\n" ); document.write( "\n" ); document.write( "In my solution,  I treat the notion/conception of a divisor to a number  N
\n" ); document.write( "as any proper divisor  AND/OR  improper divisors as the number of \" 1 \"  and the number  N  itself.\r
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\n" ); document.write( "\n" ); document.write( "Such treatment makes the solution easier;  from the other hand side,  it is not prohibited \r
\n" ); document.write( "\n" ); document.write( "by the text or the context to treat it this way.\r
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