its funny how my teacher never even talked about this and now expects us to know how to do this type of problem.. this is supposed to be an intro to chem class...
Really, it is much simpler then all that, just using your basic knowledge.
The only place for the C to come from in the CO2 is from the carbohydrate, and the only place for the hydrogens in the water to come from is the carbohydrates.
So just calculate the moles of the product, 0.0350 CO2 (and therefore C in carbohydrate) and 0.0321 H2O (and therefore H2O in the carbohydrate, not because both are H2O but because both have hydrogen and the same stoichimoetry).
Then you have the mole ratio just like many other problems you have probably done:
0.0350 Mol C = 1.09 Mol C 0.0321 Mol H2 1 Mol H2
And then to get 1.09 to a even number you multiply times 11 to get 12, and so then you have to multiply 1 mole of H2 (and therefore the H2O in the carbohydrate) by 11, to get the C12(H2O)11.