Multiple choice

From the 50 litre of milk, 5 litres of milk is taken out and after it 5 litres of water is added to the rest amount of milk. Again 5 litres of mixture of milk and water is drawn out and it was replaced by 5 litres of water. If this process is continued similarly for the third time, the amount of milk left after the third replacement: 50 लीटर दूध में से 5 लीटर दूध निकाल लिया जाता है और उसके बाद शेष दूध में 5 लीटर पानी मिला दिया जाता है। फिर से 5 लीटर दूध और पानी का मिश्रण निकाला जाता है और इसे 5 लीटर पानी से बदल दिया जाता है। यदि इस प्रक्रिया को तीसरी बार इसी तरह जारी रखा जाता है, तो तीसरे प्रतिस्थापन के बाद शेष दूध की मात्रा:

  1. 36.45 liter 36.45 लीटर

  2. 45 liter 45 लीटर

  3. 29 liter 29 लीटर

  4. 32 liter 32 लीटर

  5. None of these इनमें से कोई नहीं

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initial milk = 50L. After first replacement (remove 5L milk, add 5L water): milk = 50 - 5 = 45L. After second replacement (remove 5L of mixture which is 45/50 = 0.9 or 90% milk): milk removed = 5 * 0.9 = 4.5L, milk remaining = 45 - 4.5 = 40.5L. After third replacement: concentration = 40.5/50 = 0.81 or 81% milk. Milk removed = 5 * 0.81 = 4.05L, milk remaining = 40.5 - 4.05 = 36.45L. Option A is correct.