Directions(Q.21 to Q.30 ):

X liters of milk is taken out and replaced with water from a container having 240 liters milk. Now, 20% of the mixture is taken out and replaced with water. In final mixture, the difference in quantity of milk & water is 128 liters. Find X.

When X liter milk is taken out

Quantity of milk left = (240-X) lit

Quantity of water = X lit

When 20% of mixture taken out

Remaining quantity of milk = $frac{{80}}{{100}} imes left( {240 - X} ight)$

= (192 – 0.8X) lit

Remaining quantity of water

= $frac{{80}}{{100}} imes X + frac{{20}}{{100}} imes 240 = left( {0.8X + 48} ight)$ Lit

ATQ, (192−0.8????)−(0.8????+48)=128

16=1.6???? ⇒ ????=10