posted by Glenn .
Professor Beaker has a 50-milliliter solution containing 60% acid. How many milliliters of pure water should he add to this solution to produce a solution containing 40% acid?
see related questions below.
I've tried looking at similar problems but I'm still confused.
the amount of acid in the parts must add up to the amount in the final mix. If x ml of water (0% acid) are added, then you need
.60*50 + 0x = .40(50+x)
Now just solve for x. This assume you know what "%" means ...