Question

From 100 liter of pure milk, 10 liter of milk is taken out and 10 liter water is added. This process is repeated one more time, now the amount of water in the mixture is?
1. 81 liter
2. 71 liter
3. 19 liter 
4. 29 liter

Answer 1

Correct Answer - Option 3 : 19 liter 

Given:

100 liter of pure milk.

10 liter of milk is replaced with water two times.

Formula Used:

Final quantity = Initial quantity (1 - X/C)ⁿ,

C = capacity of a vessel

x = quantity taken out at a time

n = number of process

Calculation:

Final quantity = Initial quantity (1 - X/C)n

⇒ Final quantity = 100(1 – 10/100)²

⇒ Final quantity = 100(1 – 1/10)²

⇒ Final quantity = 100(9/10)²

⇒ Final quantity = 100 × 9/10 × 9/10

⇒ Final quantity = 81

81 liter of milk will be remaining.

Now the amount of water,

⇒ 100 – 81 

⇒ 19 

∴ The amount of water in the mixture is 19 liter.