document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=40407>Question 40407</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The irrigation system needs about 3 times as long to complete a job as another irrigation system. When both systems operate at the same time the job can be completed in 9 hrs. How long does it take the fast system to do the job alone?<BR>\n" );
document.write( "____hrs<BR>\n" );
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document.write( "Malik purchased a pair of roller blades that were originally priced at $250 for a sale price of $180. He charged the roller blades on his credit card and made the minimum monthly payment of $20. When he received his first statement, he read that the minimum finance charge for each month that there was a balance on the card that would be $15. If Malik waited until he had the $250 cash in his hand to pay for the roller blades, how much money would he save? <BR>\n" );
document.write( "Thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #25793 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=25793\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let t = the time for the faster system to do the job<BR>\n" );
document.write( "faster rate + slower rate = combined rate<BR>\n" );
document.write( "(1 job / t) + (1 job / 3t) = 1 job / 9 hours<BR>\n" );
document.write( "1/t + 1/3t = 1/9<BR>\n" );
document.write( "3t is the LCD<BR>\n" );
document.write( "3/3t + 1/3t = 1/9<BR>\n" );
document.write( "(3 + 1) / 3t = 1/9<BR>\n" );
document.write( "3t = 4*9<BR>\n" );
document.write( "t = 36/3<BR>\n" );
document.write( "t = 12 hours answer<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "1/t + 1/3t = 1/9<BR>\n" );
document.write( "1/12 + 1/(3*12) = 1/9<BR>\n" );
document.write( "1/12 + 1/36 = 1/9<BR>\n" );
document.write( "3/36 + 1/36 = 1/9<BR>\n" );
document.write( "4/36 = 1/9<BR>\n" );
document.write( "1/9 = 1/9<BR>\n" );
document.write( "OK<BR>\n" );
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document.write( "Out of the min monthly payment of $20 comes the $15 for each month <BR>\n" );
document.write( "there is a balence, so he has $5 per month to put towards the $180<BR>\n" );
document.write( "purchase <BR>\n" );
document.write( "$180 / $5/month = 36 months<BR>\n" );
document.write( "With the last payment, there is no balence due, so there's no<BR>\n" );
document.write( "finance charge. That means there's only 35 months of $15 finance charges<BR>\n" );
document.write( "($15 / month)*(35 months) = $525<BR>\n" );
document.write( "$525 + $180 = $705 total paid out<BR>\n" );
document.write( "$705 - $250 = $455 savings if he just paid $250 for roller blades </SPAN>\n" );
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