document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=545766>Question 545766</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the probability.\r<BR>\n" );
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document.write( "A lottery game has balls numbered 1 through 21. What is the probability that a randomly selected ball is an even numbered ball or a 12? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #355729 by </B><A HREF=/tutors/aboutme.mpl?userid=neatmath><B>neatmath(302)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=neatmath><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=neatmath><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=355729\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><font face=\"Tahoma\">There are 21 balls, numbered 1 through 21.<br>\r<BR>\n" );
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document.write( "How many would have even numbers?<br>\r<BR>\n" );
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document.write( "2, 4, 6, 8, 10, 12, 14, 16, 18, 20<br>\r<BR>\n" );
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document.write( "So there would be 10 with even numbers.<br>\r<BR>\n" );
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document.write( "How many would have the number 12?<br>\r<BR>\n" );
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document.write( "Just one, the 12.<br>\r<BR>\n" );
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document.write( "Now, in probability, the probability of event A OR event B happening,<br>\r<BR>\n" );
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document.write( "is the probability of event A plus the probability of event B minus the probability of both A AND B.<br>\r<BR>\n" );
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document.write( "Let A be the event of drawing an even number.<br>\r<BR>\n" );
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document.write( "Let B be the event of drawing a 12.<br>\r<BR>\n" );
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document.write( "In this case then, we are drawing 1 ball only.<br>\r<BR>\n" );
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document.write( "P(A)=10/21<br>\r<BR>\n" );
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document.write( "P(B)=1/21<br>\r<BR>\n" );
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document.write( "P(A and B)=1/21 (because 12 is both 12 AND an even number)<br>\r<BR>\n" );
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document.write( "Then P(A or B)=P(A)+P(B)-P(A and B)<br>\r<BR>\n" );
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document.write( "P(A or B)=10/21+1/21-1/21<br>\r<BR>\n" );
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document.write( "P(A or B)=10/21<br>\r<BR>\n" );
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document.write( "There is a LOT more to this subject.  Take it slow and read, read, read!<br>\r<BR>\n" );
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document.write( "Don't be afraid to ask questions.<br>\r<BR>\n" );
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document.write( "I hope this helps!  :)<br> </SPAN>\n" );
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