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Equal masses of water and of a second liquid whose density is 2 (in the same units as water's density 1) are mixed. The density of the resulting mixture is
- 2/3
- 4/3
- 3/2
- 3
Correct answer: 4/3
Solution
With equal masses, total mass = 2m and total volume = m/d1 + m/d2. Density = total mass / total volume. This gives the result 2*d1*d2/(d1+d2), the harmonic mean of the densities.
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