20 litres of a mixture contains milk and water in the ratio 3:1. How much milk must be added to this mixture to have a mixture containing milk and water in the ratio 4 :1 ?  Select the correct option:
A) 2  B) 5  C) 6  D) 7  E) 8
Quantity of milk in the given mixture = \inline \frac{20\times 3}{4}=15 lts   Quantity of water in this mixture = 20 - 15= 
<gadget id="calculator">20 - 15</gadget>
<output>5</output>
5 lts   Let x litres of milk be added to given mixture to have the requisite ratio of milk and water   Then   \inline \Rightarrow 15 + x=20   \inline \therefore x = 5   \inline \therefore Milk to be added = 5 litres   Answer:5
<result>B</result>
20 litres of a mixture contains milk and water in the ratio 3:1. How much milk must be added to this mixture to have a mixture containing milk and water in the ratio 4 :1 ?