Why do you want to use an array? The natural thing when you hear duplicate or unique is to think of hashes.

With that, use the following approach:

• loop through the file line-by line
  • split the line into fruit-name and number (using a regex)
  • use the fruit-name as key for a hash and add the number (e.g. $fruits{$fruit_name} += $number;)
• print the hash

That's all. Not too hard, isn't it?! ;-)