document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=613620>Question 613620</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Timmy has two irregular coins.  The nickel comes up heads three fifths of the time, and the quarter comes up heads two thirds of the time.  The nickel is tossed.\r<BR>\n" );
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document.write( "If the nickel comes up heads, then the quarter is tossed twice.\r<BR>\n" );
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document.write( "If the nickel comes up tails, the quarter is tossed once.  Find the probability that exactly two tails come up.  \r<BR>\n" );
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document.write( "[Nickel is 3/5 = .6; Qtr is 2/3 = .67;  .6 + .67 = 1/27 and .6 * .67 = .402<BR>\n" );
document.write( ".67 - .402 = .268\r<BR>\n" );
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document.write( "If I read this correctly, we are looking for the probability of the nickel coming up tails 2x.  So (?) to find the correct answer do I:<BR>\n" );
document.write( "1-.6 * .268 to equal .839.  Now THAT is not the correct answer!  LOL!  Your detailed explination how to find the correct answer is greatly appreciated!]\r<BR>\n" );
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document.write( "Thaning you in advance, Diane </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #386117 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=386117\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> following the tossing instructions, there are six possible outcomes<BR>\n" );
document.write( "___ hHH, hHT, hTH, hTT, tH, tT \r<BR>\n" );
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document.write( "there are two ways to get 2 tails ___ hTT or tT\r<BR>\n" );
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document.write( "like the basketball problem, the probability of any string is the product of the individual probabilities\r<BR>\n" );
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document.write( "hTT __ 3/5 * 1/3 * 1/3 = 1/15\r<BR>\n" );
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document.write( "tT ___ 2/5 * 1/3 = 2/15\r<BR>\n" );
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document.write( "these are two of the possible strings, so their probabilities add to give the probability for the 2 tail combination\r<BR>\n" );
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document.write( "probability of two tails ___ 1/15 + 2/15 = 3/15 = 1/5 = .2 </SPAN>\n" );
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