Open Script Editor, copy the script into it, and save as an application.  Drag and drop files you want to convert onto the application icon.

Saves converted files to Desktop.

Source

Open this Scriplet in your Editor:

on open theFiles

 tell application "Pages"

 repeat with aFile in theFiles

 open aFile

 set docName to name of front document

 -- Remove .pages extension. set prevTIDs to AppleScript's text item delimiters

 set AppleScript's text item delimiters to ".pages"

 -- Add .pdf extension. set docName to first text item of docName & ".pdf"

 set AppleScript's text item delimiters to prevTIDs

 -- Save file to Desktop. set docPathAndName to (path to desktop as string) & docName

 save front document as "SLDocumentTypePDF" in docPathAndName

 close front document

 end repeat

 end tell

end open