A tub contains 60 litres of milk. From this tub, 6 litres of milk was taken out and replaced with water. This whole process was repeated further two more times. How much milk is there in the tub now?

43.74 litre

The correct answer is Option (2) → 43.74 litre

Initial quantity of milk $=60$ litres

Each time $6$ litres are taken out and replaced, so fraction of milk left each time

$=1-\frac{6}{60}=\frac{54}{60}=\frac{9}{10}$

Process is repeated $3$ times

Milk left $=60\left(\frac{9}{10}\right)^3$

$=60\cdot\frac{729}{1000}$

$=\frac{43740}{1000}$

$=43.74$ litres

The quantity of milk left in the tub is $43.74$ litres.