Two wines are available for blending: one tank of 2000 L has a TA of 9.0 g/L another tank of 4000 L has a TA of 6.0 g/L. How much volume of the low acid wine do you need to mix with the 9.0 g/L TA wine to have the resulting blend equivalent to 7.2 g/L. What is the final volume of the blend?