document.write( "Question 1006173: You have two types of coins in your pockets. If you have 18 coins in total and they add up to $3.30, what are the two types of coins? (e.g. Pennies, nickels, dimes, quarters, half-dollars, dollar coins)?\r
\n" ); document.write( "\n" ); document.write( "I worked the beginning of the problem like this:\r
\n" ); document.write( "\n" ); document.write( "x+x*(18-x)=330
\n" ); document.write( "x+18x-x^2=330
\n" ); document.write( "x^2-18x+330=0
\n" ); document.write( "(x-12)(x-6)=0
\n" ); document.write( "x+6 and x=12\r
\n" ); document.write( "\n" ); document.write( "I know there are 12 quarters and 6 nickels. However, I just don't know how to set up the equation that would show you what type of coins they are. Please help. \n" ); document.write( "
Algebra.Com's Answer #622315 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "Let's do some dividing.  330 by the number of cents in\r\n" );
document.write( "the various coins:\r\n" );
document.write( "\r\n" );
document.write( "330/100 = 3.3\r\n" );
document.write( "330/50 = 6.6\r\n" );
document.write( "330/25 = 13.2\r\n" );
document.write( "330/10 = 33\r\n" );
document.write( "330/5 = 66\r\n" );
document.write( "330/1 = 330\r\n" );
document.write( "\r\n" );
document.write( "To have 18 coins, since 13.2 is closest to 18, one of the coin types\r\n" );
document.write( "has to be quarters.\r\n" );
document.write( "\r\n" );
document.write( "Hey! 13 quarters is $3.25 and 5 more cents is 18 coins and that's $3.30.\r\n" );
document.write( "\r\n" );
document.write( "So there's a solution you didn't have.\r\n" );
document.write( "\r\n" );
document.write( "Try 1 less quarter, that's 12 quarters or $3. Can we make the \r\n" );
document.write( "remaining 30 cents with 6 of the same kind of coin?  Yes 6 nickels!\r\n" );
document.write( "\r\n" );
document.write( "That's the solution you have.\r\n" );
document.write( "\r\n" );
document.write( "Try 1 less quarter, that's 11 quarters or $2.75. Can we make the\r\n" );
document.write( "remaining 55 cents with 7 of the same kind of coin?  Nope!\r\n" );
document.write( "\r\n" );
document.write( "Try 1 less quarter. That's 10 quarters or $2.50.  Can we make the\r\n" );
document.write( "remaining 80 cents with 8 of the same kind of coin?  Yes, 8 dimes!\r\n" );
document.write( "\r\n" );
document.write( "That's another solution you didn't have.\r\n" );
document.write( "\r\n" );
document.write( "No use to try for 9 quarters.  That's $2.25/ leaving $1.05, No way\r\n" );
document.write( "to have 9 of the same kind of coin totaling that.  \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "So there are three solutions\r\n" );
document.write( "\r\n" );
document.write( "10 quarters and 8 dimes.\r\n" );
document.write( "12 quarters and 6 nickels.\r\n" );
document.write( "13 quarters and 5 pennies.\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" ); document.write( "
\n" );