document.write( "Question 91966: How can I show the equations used for the solution of this problem\r
\n" ); document.write( "\n" ); document.write( " Number problems. Jill has $3.50 in nickels and dimes. If she has 50 coins, how many of each type of coin does she have?\r
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Algebra.Com's Answer #66826 by mathispowerful(115)\"\" \"About 
You can put this solution on YOUR website!
the idea is that the amount from nickels plus the amount from dimes will the the total money, that's where comes the equation.\r
\n" ); document.write( "\n" ); document.write( "Let N be # of nickels
\n" ); document.write( "Let D be # of dimes\r
\n" ); document.write( "\n" ); document.write( "we have
\n" ); document.write( " N + D = 50
\n" ); document.write( "5N + 10D = 350\r
\n" ); document.write( "\n" ); document.write( "solve this 2 by 2 system:\r
\n" ); document.write( "\n" ); document.write( "multiply the first equation by -5\r
\n" ); document.write( "\n" ); document.write( "-5N - 5D = -250\r
\n" ); document.write( "\n" ); document.write( "add to second equation, we get\r
\n" ); document.write( "\n" ); document.write( "5D = 100\r
\n" ); document.write( "\n" ); document.write( "D = 20\r
\n" ); document.write( "\n" ); document.write( "N = 50 - D
\n" ); document.write( "= 50 -20 = 30\r
\n" ); document.write( "\n" ); document.write( "so the answer is there are 30 nickels and 20 dimes.\r
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