document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=288255>Question 288255</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Okay, here goes another easy one that I can't solve:<BR>\n" );
document.write( "Printer A can print a report in 3 hours. <BR>\n" );
document.write( "Printer B can print a report in 4 hours.<BR>\n" );
document.write( "How long would it take for both printers, working together, to print the report?\r<BR>\n" );
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document.write( "I've used several different formulas and can answer the practice questions correctly, but I'm not sure HOW I'm answering them correctly, because I don't understand why I'm using this formula.\r<BR>\n" );
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document.write( "Last attempt I used:\r<BR>\n" );
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document.write( "t over 4 plus t over 3 = 1 report<BR>\n" );
document.write( "t over 4 multiplied by 3 = 3t over 12<BR>\n" );
document.write( "t over 3 multiplied by 4 = 4t over 12<BR>\n" );
document.write( "3t plus 4t over 12 = 7t over 12<BR>\n" );
document.write( "so, 7t over 12 = 1 report.<BR>\n" );
document.write( "I multiply each side by 12 (this is where I start to wonder what I'm doing...)<BR>\n" );
document.write( "So I have 84t over 12 = 12 or I have 7t = 12, <BR>\n" );
document.write( "which results in:<BR>\n" );
document.write( "t = 1 and 5 over 7.<BR>\n" );
document.write( "Can this possibly be right? <BR>\n" );
document.write( "If so, why did I multiply each side by 12 or was I supposed to divide before dividing again?<BR>\n" );
document.write( "I understand the problem in the book, but it uses 3 and 6 and I've tried several different ways,<BR>\n" );
document.write( "but they all come up with the correct answer of \"2\", so I don't know which formula is correct or why I keep getting the right answer even though I don't know what I'm doing.<BR>\n" );
document.write( "Any help or explanation is greatly appreciated, thank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #208935 by </B><A HREF=/tutors/aboutme.mpl?userid=amnd><B>amnd(23)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=amnd><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=amnd><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=208935\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I don't see what you're doing wrong. I got the same answer (12/7, or 1 and 5/7) through a similar method:<BR>\n" );
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document.write( "Rate of A: 1/3<BR>\n" );
document.write( "Rate of B: 1/4<BR>\n" );
document.write( "Time working together: x<BR>\n" );
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document.write( "The equation would then be:<BR>\n" );
document.write( "x/3 + x/4 = 1<BR>\n" );
document.write( "(4x + 3x)/12=1<BR>\n" );
document.write( "7x=12<BR>\n" );
document.write( "<b>x=12/7</b><BR>\n" );
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document.write( "You multiplied both sides to get rid of the divisor (12), I assume... Although I think an easier way would've been to simply move 12 to the expression on the right of the equation, turning the divisor into a multiplier (as I have done).<BR>\n" );
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document.write( "You might want to consider the possibility of the book rounding up the answer to the nearest hour (which is indeed \"2\"). Hope this helps. </SPAN>\n" );
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