Need help solving last part, the unknowns. (due tonight!!)

A distillotion column is a process unit in which a teed mixture is separated by multiple vaporizations and condensations to form two or more product streams. The overhead productstream is rich in the most volatile components of the feed mixture (the ones that vaporize most readilyli and the bottom product stream is rich in the least volatile components. The following flowchart shows a distillation column with two feed streams and three product streams. How many independent material balances may be written for this system? How many of the unknown flow rates and/or mole fractions must be specified before the others may be calculated? (See Example 4.3-4. Also, remember what you know about the component mole fractions of a mixture -for example, the relationship between x2 and x20) Suppose values are given for m1=2000.0kg/h and x2A=0.450. Solve for the remaining unknowns