Multiple choice

A vessel has 500 litres of milk. 50 litres of milk is replaced with 50 litres of water in this vessel. If this operation is repeated 2 more times, what is the percentage of milk in the vessel at the end?

  1. 70.0

  2. 72.9

  3. 80.0

  4. 81.0
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial milk = 500. After 1st op: 500 * (1 - 50/500) = 450. After 2nd op: 450 * 0.9 = 405. After 3rd op: 405 * 0.9 = 364.5. Percentage = (364.5 / 500) * 100 = 72.9%.

AI explanation

Using the standard replacement formula, the final quantity of milk is calculated as Initial Quantity multiplied by ((Initial Quantity minus Replaced Quantity) divided by Initial Quantity) raised to the number of operations. Substituting the given values yields 500 multiplied by ((500 minus 50) divided by 500) raised to the power of 3. This simplifies to 500 multiplied by 0.9 cubed, which equals 500 multiplied by 0.729, resulting in 364.5 litres of milk. The percentage of milk is then (364.5 divided by 500) multiplied by 100, which equals 72.9 percent.

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