Multiple choice

Milk contains $5\%$ water What quantity of pure milk should be added to $10$ litres of milk to reduce this to $2\%$.

  1. $5\ liters$
  2. $7\ liters$
  3. $11\ liters$
  4. $15\ liters$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Initial milk = 10 liters, water = 5% of 10 = 0.5 liters. Let x be the pure milk added. New water percentage = 0.5 / (10 + x) = 0.02. 0.5 = 0.02 * (10 + x) = 0.2 + 0.02x. 0.3 = 0.02x, so x = 15.

AI explanation

The 10 liters of milk contains 0.5 liters of water, and this volume must equal 2 percent of the new total. Using the percentage formula, the new total volume is 0.5 divided by 0.02, which equals 25 liters. The quantity of pure milk to add is 25 minus 10, giving 15 liters.

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