Multiple choice

From the 150 liters of a chemical solution, 15 liters of chemical solution is taken out and after it, 15 liters of water is added to the rest amount of chemical solution. Again 15 liters of chemical solution and water is drawn out and it was replaced by 15 liters of water. If this process is continued similarly for the third time, the amount of chemical solution left after the third replacement.

  1. 98.25 litres

  2. 92.4 litres

  3. 109.35 litres

  4. 90.75 litres

  5. 115.5 litres
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Each replacement keeps 135/150 = 0.9 of the chemical solution. After 3 replacements: 150 × (0.9)³ = 150 × 0.729 = 109.35 litres of the original chemical remains.

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