document.write( "Question 263943: A collection of 65 coins consisting of dimes, quarters, and half-dollars has a value of $16.30. There are two times as many quarters as dimes. Find the number of each kind of coin.
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Algebra.Com's Answer #194439 by CharlesG2(834)![]() ![]() ![]() You can put this solution on YOUR website! A collection of 65 coins consisting of dimes, quarters, and half-dollars has a value of $16.30. There are two times as many quarters as dimes. Find the number of each kind of coin.\r \n" ); document.write( "\n" ); document.write( "H half-dollar, Q quarter, D dime \n" ); document.write( "2 times as many quarters as dimes\r \n" ); document.write( "\n" ); document.write( "H + Q + D = 65 (replace Q with 2*D) \n" ); document.write( "H + 2 * D + D = 65 \n" ); document.write( "H + 3 * D = 65 (solve for H for later) \n" ); document.write( "H = 65 - 3 * D\r \n" ); document.write( "\n" ); document.write( "0.50 * H + 0.25 * Q + 0.10 * D = 16.30 (multiply both sides by 100) \n" ); document.write( "50 * H + 25 * Q + 10 * D = 1630 (replace Q with 2*D) \n" ); document.write( "50 * H + 25 * (2 * D) + 10 * D = 1630 \n" ); document.write( "50 * H + 50 * D + 10 * D = 1630 \n" ); document.write( "50 * H + 60 * D = 1630 (divide both sides by 10) \n" ); document.write( "5 * H + 6 * D = 163 (plug in H = 65 - 3 * D) \n" ); document.write( "5 * (65 - 3 * D) + 6 * D = 163 \n" ); document.write( "325 - 15 * D + 6 * D = 163 \n" ); document.write( "325 - 9 * D = 163 \n" ); document.write( "-9 * D = -162 \n" ); document.write( " 9 * D = 162 \n" ); document.write( " D = 18 \n" ); document.write( "plug in D = 18 into H = 65 - 3 * D \n" ); document.write( "H = 65 - 3 * 18 \n" ); document.write( "H = 65 - 54 \n" ); document.write( "H = 11\r \n" ); document.write( "\n" ); document.write( "so we got 18 dimes \n" ); document.write( "and since we had twice as many quarters as dimes that would be 36 quarters\r \n" ); document.write( "\n" ); document.write( "65 coins - 18 coins - 36 coins = 47 coins - 36 coins = 11 coins\r \n" ); document.write( "\n" ); document.write( "check: \n" ); document.write( "0.50 * 11 + 0.25 * 36 + 0.10 * 18 \n" ); document.write( "5.50 + 9.00 + 1.80 \n" ); document.write( "14.50 + 1.80 \n" ); document.write( "16.30 which is the amount we had and wanted\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |