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)![]() ![]() You can put this solution on YOUR website! 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 \n" ); document.write( "So, there are \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 \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 \n" ); document.write( "will be divisible by 3. \n" ); document.write( " |