document.write( "Question 976608: In a series of 5 games to be played between 2 equally matched teams, the first
\n" ); document.write( "team to win 3 games becomes the champion. Team A has won the first game. The
\n" ); document.write( "probability that team A will be the champion is ?\r
\n" ); document.write( "\n" ); document.write( "Is 3/5 incorrect?
\n" ); document.write( "Since there are 5 games, Team A won the first game. There are 4 more games left. Two more games till Team A wins or three more games till Team B wins. So obviously the probability of Team A winning is higher than Team B winning.
\n" ); document.write( "

Algebra.Com's Answer #598189 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
Here's a chart showing all of the possible combinations and probabilities for a 5 game series.
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( "
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( ".\r
\n" ); document.write( "\n" ); document.write( "Since each team is equally matched, assume that the chance of A winning a game is 0.5.
\n" ); document.write( "So the probability of each row is just the product of the probabilities.
\n" ); document.write( "A three game series would have a probability of,
\n" ); document.write( "\"P=%281%2F2%29%2A%281%2F2%29%2A%281%2F2%29=%281%2F2%29%5E3=1%2F8\"
\n" ); document.write( "Four game series,
\n" ); document.write( "\"P=%281%2F2%29%5E4=1%2F16\"
\n" ); document.write( "Five game series
\n" ); document.write( "\"P=%281%2F2%29%5E5=1%2F32\"
\n" ); document.write( "Since A already won one game, start in the second column and add up the probabilities of A winning.
\n" ); document.write( "The sum of those probabilities is 0.34375.
\n" ); document.write( "Now this is out of 0.5 instead of 1.0 since half the games have been knocked out since A won the first.
\n" ); document.write( "So the probability of A winning given they won the first is,
\n" ); document.write( "\"P=0.34375%2F0.5=11%2F16\"
\n" ); document.write( "
\n" ); document.write( "
\n" );