document.write( "Question 1172380: Two coins are tossed. what is the probability that the one coins shows heads if it is known that at least one coin is tails? \n" ); document.write( "

Algebra.Com's Answer #797412 by math_tutor2020(3817) $\"\"$ $\"About$

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\n" ); document.write( "\"at least one coin is tails\" is another way of saying \"one or more coins is tails\"\r
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\n" ); document.write( "\n" ); document.write( "Here are all the possible outcomes of flipping 2 coins
\n" ); document.write( "HH
\n" ); document.write( "HT
\n" ); document.write( "TH
\n" ); document.write( "TT
\n" ); document.write( "where H = heads and T = tails\r
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\n" ); document.write( "\n" ); document.write( "The outcomes
\n" ); document.write( "HT
\n" ); document.write( "TH
\n" ); document.write( "TT
\n" ); document.write( "all represent cases when we get at least one tail. All we've effectively done is kick out HH\r
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\n" ); document.write( "\n" ); document.write( "There are 2 cases when we get heads (HT and TH) out of three cases mentioned above.
\n" ); document.write( "The probability of showing heads, given this reduced sample space, is 2/3.\r
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\n" ); document.write( "\n" ); document.write( "If we know there's at least one tail, then the probability of getting heads is 2/3.\r
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\n" ); document.write( "\n" ); document.write( "=====================================================\r
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\n" ); document.write( "\n" ); document.write( "Answer: 2/3
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