document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=172019>Question 172019</A>: <I><SPAN STYLE=\"word-break: break-all;\"> solve the problems A and B<BR>\n" );
document.write( "A) how many liters of 4% brine solution must be added to 40 liters of 12% brine solution to dilute it to an 8% solution?\r<BR>\n" );
document.write( "\n" );
document.write( "B) A student has a test scores of 85%,78%, and 73% in beginning algebra class. what must she score on the last exam to earn a B? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #127092 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=127092\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A)  <BR>\n" );
document.write( "Letx=amount of 4% brine solution needed\r<BR>\n" );
document.write( "\n" );
document.write( "Now we know that the amount of pure salt in the 4% solution that is added(0.04x) plus the amount of pure salt in the 12% solution(0.12*40) has to equal the amount  of pure salt in the final mixture(0.08(40+x)), so our equation to solve is:\r<BR>\n" );
document.write( "\n" );
document.write( "0.04x+0.12*40=0.08(40+x)  get rid of parens (distributive)<BR>\n" );
document.write( "0.04x+4.8=3.2+0.08x subtract 3.2 and also 0.04x from each side<BR>\n" );
document.write( "0.04x-0.04x+4.8-3.2=3.2-3.2-0.04x+0.08x  collect like terms<BR>\n" );
document.write( "1.6=0.04x  divide each side by 0.04<BR>\n" );
document.write( "x=40 liters--------------------amount of 4% brine solution needed\r<BR>\n" );
document.write( "\n" );
document.write( "CK<BR>\n" );
document.write( "0.04*40+0.12*40=0.08*80<BR>\n" );
document.write( "1.6+4.8=6.4<BR>\n" );
document.write( "6.4=6.4\r<BR>\n" );
document.write( "\n" );
document.write( "B)  <BR>\n" );
document.write( "I assume an average score of 80 is a B??????<BR>\n" );
document.write( "Let x=score that she must make on the last test<BR>\n" );
document.write( "Then (85+78+73+x)/4=80  multiply each side by 4<BR>\n" );
document.write( "85+78+73+x=320 or<BR>\n" );
document.write( "236+x=320  subtract 236 from each side<BR>\n" );
document.write( "x=320-236=84----------------------------this would give her an average of 80\r<BR>\n" );
document.write( "\n" );
document.write( "CK<BR>\n" );
document.write( "(85+78+73+84)/4=320/4=80\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Hope this helps---ptaylor\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );