How would I write an equation for: Add 30 oz of 10% solution to dilute it to a 4% solution. How much water must you add? Thanks.

Question

How would I write an equation for:  Add 30 oz of 10% solution to dilute it to a 4% solution.  How much water must you add?  Thanks.

anonymous · Answer

$$.1\times 30=3$$ you have 3 ounces of "solution" say maybe scotch, and 27 ounces of water. add x amount of water and you will still have 3 ounces of scotch, but 30+x ounces total, so set 
$$27+x=.96(30+x)$$ and solve for x

anonymous · Answer

i get 45
amistre solves these as proportions, and if he were here i would ask him how

hero · Answer

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