Problem I:
Calculate the molality and mol fraction of HCl for a solution 
  which has a mass percent of 37.1 %. 
Answer:
This problem is a little different compared to problems we've 
  done in class. I did not tell you how much of the solute and the solvent is 
  available, I just gave you the percentage by weight of the solute HCl.
But that is OK we can assume any amount of solute and solvent 
  and still get the correct answer.
So you assume an amount of solute and solvent, but just remember 
  is must be 37.1% by weight HCl.