document.write( "Question 172026: a school board plans to merge 2 schools into a school of 1000 students of which 42% will be african american. One of the schools has a 10% african american student body and the3 other has a 90% african american student body. What is the studen population in each of the two schools? \n" ); document.write( "
Algebra.Com's Answer #127073 by Earlsdon(6294)\"\" \"About 
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Let x = the student population of the first school and y = the populationof the second school.
\n" ); document.write( "From the problem, you get:
\n" ); document.write( "x+y = 1000 Total student body of the combined schools.
\n" ); document.write( "0.42(1000) = 420 The number of African-American students in the combined schools.
\n" ); document.write( "x(0.1) The number of African-American students in the first school.
\n" ); document.write( "y(0.9) The number of African-American students in the second school.
\n" ); document.write( "So you have enough informtion to write two equations in two unknowns (x and y).
\n" ); document.write( "1) x+y = 1000
\n" ); document.write( "2) 0.1x+0.9y = 420 Multiply this one by 10 and rewrite in terms of x only.
\n" ); document.write( "2) 10(0.1x+0.9y) = 420 ---> x+9y = 4200 ---> x = 4200-9y Now substitute this for x in the first equation.
\n" ); document.write( "1) 4200-9y+y = 1000 Solve for y.
\n" ); document.write( "4200-8y = 1000 Subtract 4200 from both sides.
\n" ); document.write( "-8y = -3200 Divide both sides by -8
\n" ); document.write( "y = 400 and
\n" ); document.write( "x = 4200 - 9y
\n" ); document.write( "x = 4200-9(400)
\n" ); document.write( "x = 4200-3600
\n" ); document.write( "x = 600
\n" ); document.write( "The first school had 600 students.
\n" ); document.write( "The second school had 400 students. \n" ); document.write( "
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