document.write( "Question 1046531: How do you set up this problem for solving? Steve is cashing in his jar of spare nickels dimes and quarters. When he gets to the bank he receives a total of $14.70. He learned he had 133 coins in all, and that there were 3 times as many dimes as quarters. How many of each type of each type of coin did he save? \n" ); document.write( "
Algebra.Com's Answer #661962 by ikleyn(52874) You can put this solution on YOUR website! . \n" ); document.write( "How do you set up this problem for solving? Steve is cashing in his jar of spare nickels dimes and quarters. \n" ); document.write( "When he gets to the bank he receives a total of $14.70. \n" ); document.write( "He learned he had 133 coins in all, and that there were 3 times as many dimes as quarters. \n" ); document.write( "How many of each type of each type of coin did he save? \n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r\n" ); document.write( "Let n = # of nickels, d = # of dimes, q = # of quarters.\r\n" ); document.write( "\r\n" ); document.write( "Then immediately from the condition you have these system of three equations for three unknowns:\r\n" ); document.write( "\r\n" ); document.write( " n + d + q = 133, (1) (\"he had 133 coins in all\")\r\n" ); document.write( "5n + 10d + 25q = 1470, (2) (\"When he gets to the bank he receives a total of $14.70\")\r\n" ); document.write( "d = 3q. (3)\r\n" ); document.write( "\r\n" ); document.write( "Next, we reduce this 3x3 system to the more simple 2x2 system of two equations for two unknowns:\r\n" ); document.write( "\r\n" ); document.write( "For it, I substitute (replace) \"d\" in equations (1) and (2) by 3q based on equation (3). I will get\r\n" ); document.write( "\r\n" ); document.write( " n + 3q + q = 133, (4)\r\n" ); document.write( "5n + 10*(3q) + 25q = 1470. (5)\r\n" ); document.write( "\r\n" ); document.write( "or\r\n" ); document.write( "\r\n" ); document.write( " n + 4q = 133, (6)\r\n" ); document.write( "5n + 55q = 1470. (7)\r\n" ); document.write( "\r\n" ); document.write( "OK. So, you have now much simpler system (6), (7). To solve it, express n = 133-4q from (6) and substitute it into (7). You will get\r\n" ); document.write( "\r\n" ); document.write( "5*(133-4q) + 55q = 1470, or\r\n" ); document.write( "\r\n" ); document.write( "665 - 20q + 55q = 1470 ---> 35q = 1470 - 665 ---> 35q = 805 ---> q =\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Please ignore what the other tutor, \"josgarithmetic\" wrote in his post. \n" ); document.write( "He is not able to solve word problems correctly, as well to explain the solutions. \n" ); document.write( "I don't know what he is doing in this site.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Regarding the coin problems, see the lessons\r \n" ); document.write( "\n" ); document.write( " - Coin problems\r \n" ); document.write( "\n" ); document.write( " - More Coin problems\r \n" ); document.write( "\n" ); document.write( " - Solving coin problems without using equations\r \n" ); document.write( "\n" ); document.write( " - Kevin and Randy Muise have a jar containing coins\r \n" ); document.write( "\n" ); document.write( " - Typical coin problems from the archive \n" ); document.write( "in this site.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r \n" ); document.write( "\n" ); document.write( " - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |