document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=742883>Question 742883</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.<BR>\n" );
document.write( "a. what percent of student will study less than 20 hours?<BR>\n" );
document.write( "b.what percent of students will study more than 35 hours?<BR>\n" );
document.write( "c. out of a class of 200 students, how many will study between 25 and 35 hours? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #452658 by </B><A HREF=/tutors/aboutme.mpl?userid=reviewermath><B>reviewermath(1029)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=reviewermath><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=reviewermath><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=452658\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a. P(X < 20) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P%28Z+%3C+%2820+-+30%29%2F8%29 ALIGN=MIDDLE  ALT=\"P%28Z+%3C+%2820+-+30%29%2F8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "             = P(Z < -1.25)<BR>\n" );
document.write( "             = 10.56%<BR>\n" );
document.write( "b. P(X > 35) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P%28Z+%3E+%2835+-+30%29%2F8%29 ALIGN=MIDDLE  ALT=\"P%28Z+%3E+%2835+-+30%29%2F8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "             = P(Z > 0.625)<BR>\n" );
document.write( "             = 26.60%<BR>\n" );
document.write( "c. P(25 < X < 35) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P%28%2825-30%29%2F8+%3C+X+%3C+%2835-30%29%2F8%29 ALIGN=MIDDLE  ALT=\"P%28%2825-30%29%2F8+%3C+X+%3C+%2835-30%29%2F8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "                  = P(-0.625 < Z < 0.625)<BR>\n" );
document.write( "                  = 1 - 2(0.2660)<BR>\n" );
document.write( "                  = 46.8%<BR>\n" );
document.write( "  Answer: 46.8% of 200 =  93.6 &#8776; <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%2894%29 ALIGN=MIDDLE  ALT=\"highlight%2894%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > students </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );