Question

A container contains 50 litres of milk. From this container, 25 lit of milk is taken out and replaced by water. This process is repeated one more time. How much milk is there in the container now?
1. 15 litres
2. 12.5 litres
3. 50.5 litres
4. 20.5 litres
5. 25 litres

Answer 1

Correct Answer - Option 2 : 12.5 litres

Given:

Amount of milk in container = 50 litres

Amount of milk taken out and replaced by water 2 times = 25 litres

Formula used∶

Final quantity is given by = a (1 – b/a)ⁿ

Where, a = initial quantity

B = replaced quantity

n = number of times replaced

Calculation∶

Here a = 50, b = 25 and n = 2

Putting these values in the formula, we get

⇒ 50(1 – 25/50)²

⇒ 50 (1 – 0.5)²

⇒ 50 × 0.5²

⇒ 12.5

∴ Final quantity is 12.5 litres