Multiple choice

In a container having milk, 20% milk is replaced by water and this process is repeated thrice. At the end of the third operation, the percentage of pure milk in the container is

  1. 48.8

  2. 51.2

  3. 40

  4. 60

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The formula for the remaining amount of substance after n replacements is A = P(1 - r/100)^n. Here, P = 100, r = 20, and n = 3. A = 100 * (1 - 0.2)^3 = 100 * (0.8)^3 = 100 * 0.512 = 51.2%.

AI explanation

Using the formula for successive replacement, the final quantity of pure liquid is Initial Amount times (1 minus Replacement Fraction)^n. The replacement fraction is 20%, or 0.2, and the process is repeated 3 times. The remaining milk is 100 times (1 minus 0.2)^3, which equals 100 times 0.512, resulting in 51.2%.

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