Question

10L of milk contains 10% water. How much more pure milk in litres be added to this mixture to make overall percentage of milk 98% ? options are 45, 50, 40, 55​

Answer 1

Answer:

Step-by-step explanation:

The concentration of initial mixture ={10/(10+40)}*100=20%The quantity of mixture is (10+40)litres=50 litres. The final concentration to remain 40%=>The milk quantity to be in the solution=50x40%=20litres.Let the pure milk to be added=X litres with replacing X litres of ex-mixture to make the mixture contain 20 litre of milk.X litre of ex mixture contain 20%ofx milk=0.2X.After taking away X litre from the ex-mixture+> it contains (10–0.2X) litres of milk.After adding X litres of pure milk=> the milk quantity in the new solution =10–0.2X+X=10+0.8X.Now 10+0.8X=20=>0.8X+10=>X =10/0.8 .So 12.5litres of old solution to be replaced with pure milk.