SOLUTION: If 800ml of a juice drink is 15% grape juice, how much grape juice should be added to make a drink that is 20% grape juice?

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Question 77180This question is from textbook
: If 800ml of a juice drink is 15% grape juice, how much grape juice should be added to make a drink that is 20% grape juice? This question is from textbook

Answer by rajagopalan(174) About Me  (Show Source):
You can put this solution on YOUR website!
Dear Student,
You have to work cool to arrive at the answer:
Let us add x ml of grape juice to the old juice

Old Juice...800 ml....15%grape=120....ml grape juice
new Juice...800+x ml....20%grape=120+x..ml grape juice
now we get (120+x)/(800+x)=20/100 (ie 20%=20/100)
solving the first degree eqn
(120+x)/(800+x)=20/100
100(120+x)=20(800+x)
expanding 12000+100x=16000+20x
100x-20x=16000-12000
80x=4000
x=4000/80=50 ml
so you add 50 ml of fresh grape juice to make it 20% conventrate.
Cross verification:
new juice...grape=120+50=170 ml
nrw juice total =800+50 =850 ml
so % grape =170/850=20%
okay
good day !!