document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=876853>Question 876853</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It is claimed that 88 percent of first class mail (within the same city) is delivered within two days of the time of mailing. Six letters are randomly sent to different locations.\r<BR>\n" );
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document.write( "a) What is the probability that exactly four of them will arrive within two days?\r<BR>\n" );
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document.write( "b) What is the probability that at least two will arrive within two days? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #529035 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=529035\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It is claimed that 88 percent of first class mail (within the same city) is delivered within two days of the time of mailing. Six letters are randomly sent to different locations. \r<BR>\n" );
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document.write( "X~Binomial(6, 0.88)\r<BR>\n" );
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document.write( "a) What is the probability that exactly four of them will arrive within two days? \r<BR>\n" );
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document.write( "P(X = 4) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28matrix%282%2C1%2C6%2C4%29%29%280.88%5E4%29%280.12%5E2%29 ALIGN=MIDDLE  ALT=\"%28matrix%282%2C1%2C6%2C4%29%29%280.88%5E4%29%280.12%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%280.1295%29 ALIGN=MIDDLE  ALT=\"highlight%280.1295%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "b) What is the probability that at least two will arrive within two days?\r<BR>\n" );
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document.write( "P(X &#8805; 2) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sum%28%28matrix%282%2C1%2C6%2Cx%29%29%280.88%5Ex%29%280.12%5E%286-x%29%29%2Cx+=+2%2C+6%29%29 ALIGN=MIDDLE  ALT=\"sum%28%28matrix%282%2C1%2C6%2Cx%29%29%280.88%5Ex%29%280.12%5E%286-x%29%29%2Cx+=+2%2C+6%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%280.9999%29 ALIGN=MIDDLE  ALT=\"highlight%280.9999%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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