SOLUTION: Hi 1/3 of the children were boys.when 20 boys left, the number of boys decreased to 1/4 of the total number of children. How many children were at first. thanks

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: Hi 1/3 of the children were boys.when 20 boys left, the number of boys decreased to 1/4 of the total number of children. How many children were at first. thanks      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1103435: Hi
1/3 of the children were boys.when 20 boys left, the number of boys decreased to 1/4 of the total number of children. How many children were at first.
thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = the original number of children
+%281%2F3%29%2Ax+ = the original number of boys
------------------------------------------
+%281%2F3%29%2Ax+-+20+=+%281%2F4%29%2A%28+x+-+20+%29+
+%281%2F3%29%2Ax+-+20+=+%281%2F4%29%2Ax+-+5+
+%281%2F3%29%2Ax+-+%281%2F4%29%2Ax+=+15+
+%284%2F12%29%2Ax+-+%283%2F12%29%2Ax+=+15+
+%281%2F12%29%2Ax+=+15+
+x+=+180+
There were 180 children at first
-------------------------------
check:
1/3 were boys, so +180%2F3+=+60+ were boys
20 left, leaving 40 boys
The total number of children was then +180+-+20+=+160+
+40+=+%281%2F4%29%2A160+
+40+=+40+
OK
Hope this helps. Feel free to ask questions or
try another tutor