The quality of water that should be added to reduce 9 ml. Lotion containing 50 % alcohol to a lotion containing 30 % alcohol is_________?
Correct Answer: D. 6 ml Explanation: Alcohol in 9 ml lotion = (50/100 × 9)ml = 4.5ml Water in it = (9 – 4.5)ml = 4.5ml Let x ml of water be added to it, then 4.5/9+x × 100 = 30 => 4.5/9+x = 30/100 = 3/10 => 3(9+x) = 45 => 27 + 3x = 45 => 3x = 18 => x = 6 Water to be added = 6 ml
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