document.write( "Question 1046262: In my purse I have 21 coins, all of which are either 5-cent or 20-cent coins. Their total value is $2.25.
\n" ); document.write( "How many 20-cent coins do I have? \n" ); document.write( "

Algebra.Com's Answer #661742 by ikleyn(52786) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "In my purse I have 21 coins, all of which are either 5-cent or 20-cent coins. Their total value is $2.25.
\n" ); document.write( "How many 20-cent coins do I have?
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "Let t is the number of 20-cent coins in the purse.\r\n" );
document.write( "Then the number of the 5-cent coins is (21-t).\r\n" );
document.write( "\r\n" );
document.write( "20-cent coins contribute 20t       cents into the total.\r\n" );
document.write( " 5-cent coins contribute  5*(21-t) cents into the total.\r\n" );
document.write( "\r\n" );
document.write( "The balance equation is\r\n" );
document.write( "\r\n" );
document.write( "20t + 5*(21-t) = 225.\r\n" );
document.write( "\r\n" );
document.write( "Simplify and solve it for t:\r\n" );
document.write( "\r\n" );
document.write( "20t + 105 - 5t = 225,  or\r\n" );
document.write( "\r\n" );
document.write( "20t - 5t = 225 - 105,  or\r\n" );
document.write( "\r\n" );
document.write( "15t = 120,\r\n" );
document.write( "\r\n" );
document.write( "t =  = 8.\r\n" );
document.write( "\r\n" );
document.write( "Answer. There are 8 20-cent coins in the purse.\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "For more solved problems on coins 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\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );