SOLUTION: Ben nordstrom is developing film in his darkroom when he realizes he does not have the proper developer. He needs a mixture that is 20% developer, but he only has a mixture that is

Question 280038: Ben nordstrom is developing film in his darkroom when he realizes he does not have the proper developer. He needs a mixture that is 20% developer, but he only has a mixture that is 90% developer. How much pure water must be mixed with 2 pints of 90% developer to produce the mixture he needs?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Ben nordstrom is developing film in his darkroom when he realizes he does not have the proper developer. He needs a mixture that is 20% developer, but he only has a mixture that is 90% developer. How much pure water must be mixed with 2 pints of 90% developer to produce the mixture he needs?
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2 pints of 90% contains 1.8 pints of developer
That 1.8 pints is to be 20% in the new mix
--> the total = 9.0 pints
9 - 2 = 7 pints of water to be added

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