Rini has mixed two colours 'C₁' and 'C₂' in the ratio 2 ∶ 3. If the rate of the colour 'C₁' is ₹500 per unit and she is selling the mixture of the two colours at ₹650 per unit at breakeven price, then what is the rate (in ₹) per unit of the second colour, that is, ' C₂'?

A vessel is filled with liquid, 5 parts of which are water and 11 parts syrup. What part of the mixture must be drawn off and replaced with water so that the mixture may be syrup and water in the ratio 3 ∶ 2?