Correct Answer - Option 4 : 80 litres
Given:
Initial concentration = 270 litre
Final concentration = x litre
Quantity removed in each cycle = 90 litre
The process is repeated one more times means: n = 3
Formula:
FC = IC × (1 – Quantity removed in each cycle/total IC)n
Here,
FC = final concentration
IC = Initial concentration
n = The process repeated how many times
Calculation:
We know that –
FC = IC × (1 – Quantity removed in each cycle/total IC)n…….(1)
Put all the given values in equation (1) then we get
x = 270 × (1 – 90/270)3
⇒ x = 270 × (1 – 1/3)3
⇒ x = 270 × (2/3)3
⇒ x = 270 × 8/27
⇒ x = 10 × 8
x = 80
∴ The quantity of milk in the container after final replacement will be 80 litres