500 ml of water is mixed with 1 litre of milk and this mixture is filled in 2 bottles of equal capacity. Mixture in each bottle is 700 mL.
Bottle 1 contains a mixture of milk and water in 7:2 ratio and Bottle 2 contains a mixture of milk and water in 9:4 ratio. In what ratio of volumes should the liquids in Bottle 1 and Bottle 2 be combined to obtain a mixture of milk and water in 3:1 ratio?