document.write( "Question 936452: A school is divided into two parts. Upper school and lower school.
\n" ); document.write( "Upper school has 300 boys and 200 girls.
\n" ); document.write( "Lower School has 400 boys and 300 girls.
\n" ); document.write( "A student is selected at random from the school.
\n" ); document.write( "If the first student comes from the lower school, a second student is selected at random from the upper school, if the first student comes from the upper school, a second student is selected at random from the lower school.\r
\n" ); document.write( "\n" ); document.write( "Find the probability that the second student will be a girl. \n" ); document.write( "

Algebra.Com's Answer #570258 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!

\r\n" );
document.write( "\"or\" --> add probabilities\r\n" );
document.write( "\"&\" = \"and\" --> multiply probabilities\r\n" );
document.write( "\r\n" );
document.write( "L = lower\r\n" );
document.write( "U = upper\r\n" );
document.write( "G = girl\r\n" );
document.write( "B = boy\r\n" );
document.write( "\r\n" );
document.write( "We want \r\n" );
document.write( "\r\n" );
document.write( "P(L&G&G or L&B&G or U&G&G or U&B&G) =\r\n" );
document.write( "\r\n" );
document.write( "P(L&G&G) + P(L&B&G) + P(U&G&G) + P(U&B&G)\r\n" );
document.write( "\r\n" );
document.write( "P(L) = \r\n" );
document.write( "P(U) = \r\n" );
document.write( "P(G from U) = \r\n" );
document.write( "P(B from U) = \r\n" );
document.write( "P(G from L) = \r\n" );
document.write( "P(B from L} = \r\n" );
document.write( "\r\n" );
document.write( "P(L&G&G) = (1/2)(3/7)(2/5) =  6/70\r\n" );
document.write( "P(L&B&G) = (1/2)(4/7)(2/5) =  8/70\r\n" );
document.write( "P(U*G&G) = (1/2)(2/5)(3/7) =  6/70\r\n" );
document.write( "P(U*B*G) = (1/2)(3/5)(3/7) =  9/70\r\n" );
document.write( "----------------------------------\r\n" );
document.write( "                    TOTAL  = 29/70\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( "

\n" );