Multiple choice

A vessel contains 60 liters of pure milk. 12 liters of milk is drawn off and replaced with an equal amount of water. This operation is repeated one more time. What is the remaining quantity of pure milk in the vessel?

  1. 36 liters

  2. 38.4 liters

  3. 40.2 liters

  4. 42 liters

  5. 43.2 liters
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The formula for remaining amount after n replacements is Initial * (1 - replaced/total)^n. Here, 60 * (1 - 12/60)^2 = 60 * (4/5)^2 = 60 * 16/25 = 60 * 0.64 = 38.4 liters.

AI explanation

Using the replacement formula, the final quantity of pure milk is calculated as Initial Amount times (1 minus Amount Replaced divided by Total Amount) raised to the power of the number of operations. Substituting the given values gives 60 times (1 minus 12 divided by 60) squared, which simplifies to 60 times (4 divided by 5) squared. This equals 60 times 16 divided by 25, resulting in 38.4 liters.

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