document.write( "Question 979180: Find the total number of pairs of (x,y) satisfying the equation 3x+5y=100, x and y are positive integers
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Algebra.Com's Answer #600473 by anand429(138)![]() ![]() You can put this solution on YOUR website! 3x + 5y =100 \n" ); document.write( "=> y = (100-3x)/5 \n" ); document.write( "Since x and y are both positive integer, \n" ); document.write( "so x has to lie between 1 and 33 -------------(condition 1) \n" ); document.write( "Now y is a integer, hence (100-3x) must be a multiple of 5 \n" ); document.write( "For(100-3x) to be a multiple of 5, 3x also has to be multiple of 5 \n" ); document.write( "which is possible only when x is a multiple of 5 -----(condition 2) \n" ); document.write( "So, possible values of x meeting conditions 1 and 2 are:- \n" ); document.write( "x= 5,10,15,20,25,30 \n" ); document.write( "Hence , all possible required pairs of x and y are:- \n" ); document.write( "5,17 \n" ); document.write( "10,14 \n" ); document.write( "15,11 \n" ); document.write( "20,8 \n" ); document.write( "25,5 \n" ); document.write( "30,2 \n" ); document.write( " |