How much water must be added to dilute 9 ml of a lotion containing 50% alcohol down to 30% alcohol_________?
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Answer: D. 6 ml
Explanation
The initial amount of pure alcohol in nine milliliters of lotion is calculated by multiplying nine by zero point five. Setting up the dilution equation with an unknown added water volume x gives four point five divided by nine plus x equal to zero point three. Solving this linear equation results in nine plus x equaling fifteen, meaning six milliliters of water must be added. Solution concentration is defined as the volume of solute divided by the total volume of the mixture. Dilution problems maintain a constant amount of solute while increasing the total liquid volume with solvent. Algebraic proportions provide a reliable method for determining unknown volumes in chemical dilutions.
Option A underestimates the required water volume to dilute the lotion down to thirty percent. Option B is incorrect because adding four milliliters fails to satisfy the target concentration equation. Option C falls short of the exact volume calculated through the standard dilution formula.
- Subject
- Mathematics
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- Mathematics
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- —
- Difficulty
- medium
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