document.write( "Question 1163319: You are given two urns, each containing a collection of coloured balls. Urn 1 contains three white and two blue balls. Urn 2 contains four white and three blue balls. A ball is drawn at random from urn 1 and put into urn 2. A ball is then picked a random from Urn 2.
\n" ); document.write( "What is the probability that the ball picked is white? Assume balls picked from an urn are equally likely to be any of the balls present.
\n" ); document.write( "

Algebra.Com's Answer #787381 by ikleyn(52800)\"\" \"About 
You can put this solution on YOUR website!
.
\n" ); document.write( "You are given two urns, each containing a collection of coloured balls.
\n" ); document.write( "Urn 1 contains three white and two blue balls.
\n" ); document.write( "Urn 2 contains four white and three blue balls.
\n" ); document.write( "A ball is drawn at random from urn 1 and put into urn 2.
\n" ); document.write( "A ball is then picked a random from Urn 2.
\n" ); document.write( "What is the probability that the ball picked is white? Assume balls picked from an urn are equally likely to be any of the balls present.
\n" ); document.write( "~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r\n" );
document.write( "(1)  Analyzing the first step, when we draw the ball from Urn 1 and put it into Urn 2:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "         After the first step, we draw the white ball from Urn 1 with the probability of  \"3%2F%283%2B2%29\" = \"3%2F5\" and put it into Urn 2.\r\n" );
document.write( "\r\n" );
document.write( "         So, with the probability  \"3%2F5\"  we get the content (5white,3blue) in the Urn 2 at this step.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "         Alternatively, with the complement probability  \"2%2F5\"  we get the content (4white,4blue) in Urn 2 at this step.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "(2)  Analyzing the second step, when we draw a ball from Urn 2, we have two respective alternatives\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "         we draw a white ball from Urn 2  (5w,3b)  with the probability  \"5%2F%285%2B3%29\" = \"5%2F8\",  or\r\n" );
document.write( "\r\n" );
document.write( "         we draw a white ball from Urn 2  (4w,4b)  with the probability  \"4%2F%284%2B4%29\" = \"4%2F8\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "(3)  Now the probability to have finally a white ball from Urn 2 is\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "         P = \"%283%2F5%29%2A%285%2F8%29\" + \"%282%2F5%29%2A%284%2F8%29\" = \"15%2F40\" + \"8%2F40\" = \"23%2F40\".    ANSWER\r\n" );
document.write( "
\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );