Process engineering mass balance in the douglas aproach

[latkan]

Hey guys i was hoping for some help with the mass balance of the equations for the production of styrene from ethylbenzene. I have attached my problem sheet and my answer sheet, q 7 is what i am stuck on please help me i am confused

 

[Tom Creswell]

Mole proportions of each species are
EB= 0.98 - x-y-z
Styrene= x
H2= x-z
Bz = y+0.02, ethylene= y
Tol and methane= z
-----------------
Specify x= 0.3, 0.4, 0.5, 0.6
Then Figure out y, z as a function of x (two formulas)
Prorate all the moles above to get the right amount of product.
Do economics on the products and fuel requirements, to see where you are.