document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1124683>Question 1124683</A>: <I><SPAN STYLE=\"word-break: break-all;\"> There are 5 red and 7 black identical balls in a bag. Peter picks two balls from the bag at random one after the other without replacement. Find the probability that he picked<BR>\n" );
document.write( "(a) two balls that were of the same colour. <BR>\n" );
document.write( "(b) at least one red.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #741011 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=741011\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> two of same color means both red or both black<BR>\n" );
document.write( "for red (5/12)(4/11) or 20/132 \r<BR>\n" );
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document.write( "for black (7/12)(6/11) or 42/132 \r<BR>\n" );
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document.write( "Those probabilities don't overlap, so the combined is 62/132 or 0.47\r<BR>\n" );
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document.write( "At least one red is 1- probability of no red<BR>\n" );
document.write( "That probability is 42/132 from above, so the answer is 90/132 or 0.68 </SPAN>\n" );
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