title: Finding element in list in Scheme
body: <p>i'm very beginner of Scheme and try to figure out how it is functioning; so i want to write a basic code:
  first of all i have a definition set:    <em>zipcode (ZIPCODE CITY STATE)</em></p>
  
  <pre><code>(define zipcodes '(
   (96774 ookala hawaii)
   (90001 losangeles california)
   (90263 malibu california)
   (10044 newyork newyork)
   ))
  </code></pre>
  
  <p>i try to write a function that input is zipcode and return city and state name for example:</p>
  
  <pre><code> &gt;(find '10044)
   (list 'newyork 'newyork)
  
   &gt;(find '99999)
   empty because there is not zipcode like that.
  </code></pre>
  
  <p>Thanks a lot...</p>
  
  <p>I'm not allowed to us LET function</p>