How many litres of water must be added to 16 liters of milk and water containing 10% water to make it 20% water in it?  Select the correct option:
A) 2 litre B) 4 litre C) 6 litre D) 7 litre E) 9 litre
By rule of alligation,   % Concentration   of water in pure water (100)	% Concentration   of water in the given mixture (10)   Mean % concentration   (20)   20 - 10= 
<gadget id="calculator">20 - 10</gadget>
<output>10</output>
10	100 - 20= 80   =&gt; Quantity of water : Quantity of the mixture = 10 : 80 = 1 : 8   Here quantity of the mixture = 16 litres   =&gt; Quantity of water : 16 = 1 : 8   =&gt; Quantity of water   =   16   ×   1   8   =   2   =16×18=2 litre   2 litre)
<result>A</result>
How many litres of water must be added to 16 liters of milk and water containing 10% water to make it 20% water in it?