1. Discover ambiguities and omissions in the following statement of requirements
   for part of a ticket issuing system.

  "An automated ticket issuing system sells rail tickets. Users select their
  destignation, and input a credit card and a personal identification number. 
  The rail ticket is issued and their credit card account charged with it cost.
  When the user presses the start button, a menu display of potential 
  destignations is activated along with a message to the user to select a 
  destignation. Once a destignation has been selected, users are requested to 
  input their credit card. Its validity is checked and the user is then 
  requested to input a personal identifier. When the credit transaction has 
  been validated, the ticket is issued." 


2. Describe three different types of non-functional requirement wich may be 
   placed on a system. Give example of each of these types of requirement.