document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=678610>Question 678610</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The height h(t), in feet, of an airborn tee-shirt t seconds after being launched can be approximated by h(t)=-15t^2+105t+10, 0<= t <=10.  Find the time when the shirt will reach a fan 160ft above ground level? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #421558 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=421558\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">     The height h(t), in feet, of an airborn tee-shirt t seconds after being launched can be approximated by h(t)=-15t^2+105t+10, 0<= t <=10. Find the time when the shirt will reach a fan 160ft above ground level?<BR>\n" );
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document.write( "set h(t) to 160 and solve for t:<BR>\n" );
document.write( "h(t)=-15t^2+105t+10<BR>\n" );
document.write( "160=-15t^2+105t+10<BR>\n" );
document.write( "0=-15t^2+105t-150<BR>\n" );
document.write( "0=15t^2-105t+150<BR>\n" );
document.write( "0=t^2-7t+10<BR>\n" );
document.write( "0=(t-2)(t-5)<BR>\n" );
document.write( "t = {2, 5}<BR>\n" );
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document.write( "answer: at 2 secs and again at 5 secs<BR>\n" );
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