document.write( "Question 313391: How many three digit numbers are such that the product of their digits is 120? \n" ); document.write( "
Algebra.Com's Answer #224067 by toidayma(44)![]() ![]() You can put this solution on YOUR website! Firstly, we have 120 = 2^3*3*5 \n" ); document.write( "since each digit is smaller than 10, therefore, one digit must be 5. We have 2 digits left with product of 2^3*3 \n" ); document.write( "there are only two case for one digit that has the factor of 3: 3, 3*2 (3*2^2 is larger than 9) \n" ); document.write( "So there are totally two 3-digit sets that has the product of 120: (5,3,8) and (5,6,4) \n" ); document.write( "With each set, we have 3! different digits that satisfied the product of the three digits is 120. \n" ); document.write( "Thus, there are totally 2*3! = 12 such digits. \n" ); document.write( " |