SOLUTION: A bag contains some balls of which 1/4 are red. forty more balls of which 5 are red are added. if 1/5 of all the balls are red, how many balls were there originally?

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Question 314848: A bag contains some balls of which 1/4 are red. forty more balls of which 5 are red are added. if 1/5 of all the balls are red, how many balls were there originally?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Originally you had 4N balls, N of them were red.
5 red balls and 35 non-red balls are now added.
The total number of red balls is now N%2B5
The total number of balls is 4N%2B40.
(1/5) of the new total are red.
%281%2F5%29%284N%2B40%29=N%2B5
4N%2B40=5N%2B25
N=40-25
highlight%28N=15%29
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Verify.
You originally had 15 red balls, and 60 total balls (15/60=1/4).
Then you added the additional balls.
You then had 20 red balls and 100 total balls (20/100=1/5).