repost: conditional sum?
 

Don't bother using formula.

You can do this using the subtotal function.
In the Excel Menu, use Data, then Sub-total
(Make sure your list is sorted on the Fruit column.)

Or, and this is a million times more interesting, ...
Get your head into Pivot tables.

Pivot tables can do what you're trying to do.
They are the real XL number crunchers.

Yipeeeeeeeee