document.write( "Question 887110: consider the following statements:
\n" ); document.write( "A number a1a2a3a4a7 is divisible by 9 if
\n" ); document.write( "1.a1+a2+a3+a4+a7 is divisible by9.
\n" ); document.write( "2.a1-a2+a3-a4+a7 is divisible by 9.
\n" ); document.write( "which of the above statements is correct?
\n" ); document.write( "a.1 only.
\n" ); document.write( "b.2 only.
\n" ); document.write( "c. both 1 and 2. \n" ); document.write( "
Algebra.Com's Answer #536724 by Edwin McCravy(20059)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Let's find a random 5 digit numbers that is\r\n" );
document.write( "divisible by 9 and see which one or both are true.\r\n" );
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document.write( "Take an arpitrary 5 digit number, say 79269\r\n" );
document.write( "Divide it by 9\r\n" );
document.write( "Get 8807.6666666\r\n" );
document.write( "So if we take 8807x9 we get a five-digit number 79263, \r\n" );
document.write( "which is divisible by 9.\r\n" );
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document.write( "Then a1=7, a2=9, a3=2, a4=6, a7=3  [Why the 7 subscript instead of 5???]\r\n" );
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document.write( "a1+a2+a3+a4+a7 = 7+9+2+6+3 = 27, which is divisible by 3, so 1 is true\r\n" );
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document.write( "a1-a2+a3-a4+a7 = 7-9+2-6+3 = -3 not divisible by 9.  So 2 is not true.\r\n" );
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document.write( "Answer: Only the first one is true.\r\n" );
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document.write( "Edwin
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