document.write( "Question 374811: how many 13 digit numbers are possible by using the digits 1,2,3,4,5 which are divisible by 4 if repetition of digits is allowed? \n" ); document.write( "
Algebra.Com's Answer #269959 by richard1234(7193)![]() ![]() You can put this solution on YOUR website! The last two digits must be a multiple of 4. This means that the last two digits must be either 12, 24, 32, 44, or 52 (as these are the only two digit multiples of 4 possible with these digits)\r \n" ); document.write( "\n" ); document.write( "There are five ways to choose one of these 2-digit combinations. The other 11 digits don't matter, and are mutually exclusive to each other so there are 5^11 ways to choose these 11 digits.\r \n" ); document.write( "\n" ); document.write( "Therefore the total number of ways is 5*(5^11) = 5^12 = 244,140,625 ways. \n" ); document.write( " |