document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1161595>Question 1161595</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Amanda made an extra $70,00 last year from a part time job. She invested part of the money at 10% and the rest at 7%. She made a total of $6400 in interest. How much was invested at 7% </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #785195 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13215)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=785195\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "(1) A traditional algebraic setup for solving....<br><BR>\n" );
document.write( "x = amount at 10%<BR>\n" );
document.write( "70000-x = amount at 7%<br><BR>\n" );
document.write( "10% of x, plus 7% of (70000-x), equals 6400:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.10%28x%29%2B.07%2870000-x%29+=+6400 ALIGN=MIDDLE  ALT=\".10%28x%29%2B.07%2870000-x%29+=+6400\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Solve using basic algebra....<br><BR>\n" );
document.write( "--------------------------------------------<br><BR>\n" );
document.write( "(2) A quick and easy way to solve a 2-part \"mixture\" problem like this, if an algebraic solution is not required....<br><BR>\n" );
document.write( "(1) All $70,000 invested at 10% would yield $7000 interest; all at 7% would yield $4900 interest.<br><BR>\n" );
document.write( "(2) The actual interest, $6400, is 5/7 of the way from $4900 to $7000.  ($4900 to $7000 is a difference of $2100; $4900 to $6400 is a difference of $1500; 1500/2100 = 5/7)<br><BR>\n" );
document.write( "(3) That means 5/7 of the total was invested at the higher rate.<br><BR>\n" );
document.write( "ANSWER: 5/7 of $70,000, or $50,000, at 10%; the other $20,000 at 7%.<br><BR>\n" );
document.write( "CHECK:<BR>\n" );
document.write( ".10(50000) + .07(20000) = 5000+1400 = 6400<br><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );