A container contains 50 litres of milk. From that 8 litres of milk was taken out and replaced by water. This process was repeated further two times. How much milk is now contained by the container?

We are given:

• Initial quantity of milk = 50 litres
• At each step, 8 litres of the current mixture is removed and replaced with water.
• This process is repeated 3 times in total.

Key Concept: When a fixed quantity is repeatedly removed and replaced, the remaining quantity of original substance after n operations is given by:

Remaining Milk = Initial Milk × (1 - Quantity Removed / Total Volume)n

Here,

• Initial Milk = 50 litres
• Quantity Removed = 8 litres
• Total Volume = 50 litres
• n = 3 times

Apply the formula:

Remaining Milk = 50 × (1 - 8/50)3
               = 50 × (42/50)3
               = 50 × (21/25)3

Calculate:

(21/25)3 = 9261 / 15625 ≈ 0.5927
Remaining Milk ≈ 50 × 0.5927 ≈ 29.63 litres

Answer: Approximately 29.63 litres of milk remains in the container.