document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1082468>Question 1082468</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The probability of passing a class is 60%. What is the probability that 1 out of 20 students pass the class?\r<BR>\n" );
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document.write( "A) 1.2*10^-4%<BR>\n" );
document.write( "B) 2.3*10^-4%<BR>\n" );
document.write( "C) 3.3*10^-5%<BR>\n" );
document.write( "D) 5.6*10^-5% </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #696615 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=696615\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the formula for the binomial probability is:\r<BR>\n" );
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document.write( "p(x) = p^x * q^(n-x) * c(n,x)\r<BR>\n" );
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document.write( "when p = .6, q = .4 because q = 1 - p.\r<BR>\n" );
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document.write( "when x = 1 and n = 20, the formula becomes:\r<BR>\n" );
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document.write( "p(1) = .6^1 * .4^19 * c(20,1)\r<BR>\n" );
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document.write( "c(20,10) is the combination formula of c(n,x) = n! / (x!*(n-x)!)\r<BR>\n" );
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document.write( "when n = 20 and x = 1, this formula becomes c(20,1) = 20! / (1! * 19!)\r<BR>\n" );
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document.write( "this can be written as c(20,1) = (20 * 19!) / (1! * 19!)\r<BR>\n" );
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document.write( "simplify this to get c(20,1) = 20/1 = 20\r<BR>\n" );
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document.write( "p(1) = .6^1 * .4^19 * c(20,1) becomes p(1) = .6^1 * .4^19 * 20.\r<BR>\n" );
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document.write( "solve for p(1) to get p(1) = 3.298534883 * 10^(-7)\r<BR>\n" );
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document.write( "round this to 1 decimal digit and this becomes p(1) = 3.3 * 10^(-7)\r<BR>\n" );
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document.write( "multiply this by 100 to make it a percent and you get p(1) = 330 * 10^(-7)%\r<BR>\n" );
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document.write( "convert this to scientific format to get p(1) = 3.3 * 10^(-5)%\r<BR>\n" );
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document.write( "to convert to scientific format, there must be only 1 digit to the left of the decimal point\r<BR>\n" );
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document.write( "330 * 10^(-7)% has 3 digits to the left of the decimal point because the decimal point is implied after the 330.\r<BR>\n" );
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document.write( "it actually looks like 330. * 10^(-7)%\r<BR>\n" );
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document.write( "to get it to be 3.3, you have to divide 330 by 100 and multiply 10^(-7) by 100.\r<BR>\n" );
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document.write( "you would get p(1) = 3.3 * 10^(-7) * 100\r<BR>\n" );
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document.write( "10^(-7) * 100 is the same as 10^(-7) * 10^2 which results in 10^(-7+2) which results in 10^(-5)\r<BR>\n" );
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document.write( "you end up with p(1) = 3.3 * 10^(-5)%.\r<BR>\n" );
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document.write( "that looks like selection C.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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