SOLUTION: when 6 boys were admitted and 6 girls were left from class the percentage of boys in the class increased from 60% to 75%,find the orignal no. of boys and girls in the class.also gi

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: when 6 boys were admitted and 6 girls were left from class the percentage of boys in the class increased from 60% to 75%,find the orignal no. of boys and girls in the class.also gi      Log On


   

Question 617077: when 6 boys were admitted and 6 girls were left from class the percentage of boys in the class increased from 60% to 75%,find the orignal no. of boys and girls in the class.also give the graphical soltuion
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = original number of boys
Let +y+ = original number of girls
given:
(1) +x+%2F+%28+x+%2B+y+%29+=+.6+
and
(2) +%28+x+%2B+6+%29+%2F+%28+x+%2B+6+%2B+y+-+6+%29+=+.75+
---------
(2) +%28+x+%2B+6+%29+%2F+%28+x+%2B+y+%29+=+.75+
(2) +x+%2B+6+=+.75%2A%28+x+%2B+y+%29+
(2) +x+%2B+6+=+.75x+%2B+.75y+
(2) +.75y+=+.25x+%2B+6+
Divide both sides by +.25+
(2) +3y+=+x+%2B+24+
(2) +y+=+%281%2F3%29%2Ax+%2B+8+
and, also
(1) +x+%2F+%28+x+%2B+y+%29+=+.6+
(1) +x+=+.6%2A%28+x+%2B+y+%29+
(1) +x+=+.6x+%2B+.6y+
(1) +.6y+=+.4x+
(1) +y+=+%282%2F3%29%2Ax+
-----------------
+%281%2F3%29%2Ax+%2B+8+=+%282%2F3%29%2Ax+
+%281%2F3%29%2Ax+=+8+
+x+=+24+
and
(2) +y+=+%281%2F3%29%2A24+%2B+8+
(2) +y+=+8+%2B+8+
(2) +y+=+16+
Originally, there were 24 boys and 16 girls
Here's the graphical solution: