document.write( "Question 1067319: How many 3 digit palindromes are divisible by 3? Thanks for any help . \n" ); document.write( "
Algebra.Com's Answer #682520 by KMST(5328)\"\" \"About 
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While the middle digit could be any of the 10 digits, including 0,
\n" ); document.write( "he first and last digits cannot be zero.
\n" ); document.write( "They must be one of the \"9\" choices from 1 though 9.
\n" ); document.write( "So, there are \"9%2A10=90\" 3-digit palindromes,
\n" ); document.write( "For a number to be divisible by 3 , the sum of the digits must be divisible by 3.
\n" ); document.write( "Of the 9 choices for first (and last) digit, 3 are multiples of 3,
\n" ); document.write( "another 3 have a remainder of 1 when divided by 3,
\n" ); document.write( "and the other 3 have a remainder of 2.
\n" ); document.write( "For any middle digit, there will be \"3\" out of the \"9\" choices of first and last digits that will make the sum of digits a multiple of 3.
\n" ); document.write( "If the middle digit is has a remainder of 0 when divided by 3 (as happens for 0, 3, or 9),
\n" ); document.write( "a first/last digit that is a multiple of 3 makes the sum a multiple of 3.
\n" ); document.write( "If you the middle digit has a remainder of 1 when divided by 3,
\n" ); document.write( "a first/last digit with a reminder of 1,
\n" ); document.write( "will make the 3 remainders add up to 3,
\n" ); document.write( "for a sum that is a multiple of 3.
\n" ); document.write( "If you the middle digit has a remainder of 2 when divided by 3,
\n" ); document.write( "a first/last digit with a reminder of 2,
\n" ); document.write( "will make the 3 remainders add up to 6,
\n" ); document.write( "for a sum that is a multiple of 3.
\n" ); document.write( "Of the \"90\" palindromes, \"1%2F3\" or \"90%2F3=highlight%2830%29\"
\n" ); document.write( "will be divisible by 3.
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