document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=86219>Question 86219</A>: <I><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "7.	Michael is shopping for a new CD player with a built-in alarm clock. Electronics City has a special coupon for $30 off any CD player and is also having a sale with a 25% discount on any alarm clock.<BR>\n" );
document.write( "a. Write a function rule to model a 25%-off sale, and a function rule to model a $30-off coupon.\r<BR>\n" );
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document.write( "b. Use composition of functions to model how much Michael would pay for a CD alarm clock if the clerk applies the discount first and then the coupon.\r<BR>\n" );
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document.write( "c. Use composition of functions to model how much Michael would pay for a CD alarm clock if the clerk applies the coupon first and then the discount.\r<BR>\n" );
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document.write( "d. Michael selects a CD alarm clock with a regular price of $150. How much more will the item cost if the clerk applies the coupon first?\r<BR>\n" );
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document.write( "e. Why does the CD alarm clock cost less if the discount is applied after the coupon?\r<BR>\n" );
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document.write( "8.	The radius of a balloon is given by r = 0.3t, where t is the time it takes to blow up the <BR>\n" );
document.write( "      balloon.  The volume of a sphere is given by V=4/3IIr^3\r<BR>\n" );
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document.write( "a)	Find an equation for the composite function V(r(t)).<BR>\n" );
document.write( "b)	What is the input and output of the composite function?<BR>\n" );
document.write( "c)	Find the Volume of a balloon 5 seconds after blowing it up.\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #62397 by </B><A HREF=/tutors/aboutme.mpl?userid=scianci><B>scianci(186)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scianci><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=62397\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 7. let x = original price of CD player<BR>\n" );
document.write( "a. 25% off: .75x  [after deducting 25%, the price is 75% of what it was initially]<BR>\n" );
document.write( "$30 off: x - 30<BR>\n" );
document.write( "b. .75x - 30<BR>\n" );
document.write( "c. .75(x - 30)<BR>\n" );
document.write( "d. .75(150 - 30) = .75(120) = $90<BR>\n" );
document.write( "e. because by applying the discount first the initial price is lowered by 25%, then $30 is taken off the lower price. Otherwise, you'd be deducting $30 from the full price instead of from the lowered price, then taking 25% off the reduced price, which is less of a deduction than taking 25% of the full original price.<BR>\n" );
document.write( "8a. V(r(t)) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F3 ALIGN=MIDDLE  ALT=\"4%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" >pi*<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%280.3t%29%5E3 ALIGN=MIDDLE  ALT=\"%280.3t%29%5E3\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F3 ALIGN=MIDDLE  ALT=\"4%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" >pi*<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.027t%5E3 ALIGN=MIDDLE  ALT=\"0.027t%5E3\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 0.036pi<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5E3 ALIGN=MIDDLE  ALT=\"t%5E3\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%2Api%2At%5E3%2F250 ALIGN=MIDDLE  ALT=\"9%2Api%2At%5E3%2F250\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "b. input is t [time] and output is V [volume]<BR>\n" );
document.write( "c. V = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%2Api%2A5%5E3%2F250 ALIGN=MIDDLE  ALT=\"9%2Api%2A5%5E3%2F250\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%2Api%2F2 ALIGN=MIDDLE  ALT=\"9%2Api%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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