Brain Teasers
How Much Brine is in the Tank?
There is a brine in a storage tank that contains 2.5% sodium chloride (NaCl)in water. When you add another kilogram of NaCl the concentration goes up to 3%.
How much brine was originally in the storage tank?
How much brine was originally in the storage tank?
Answer
Let there be X kg of NaCl and W kg of water in the original solution.From the first statement,
X / (X + W) = 2.5% = 0.025 ---- (1)
After adding 1 kg of NaCl,
(X + 1) / (X + 1 + W) = 3% = 0.03 ---- (2)
From (1): (X + W) / X = 1 / 0.025 = 40
(1a): W = 39X
From (2): (X + 1) / (X + 1 + 39 X) = 0.03
(2a): X = 4.85 kg
(1b): W = 189.15 kg
X + W = 194 kg (original amount of brine in storage tank)
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