No way of telling context in this sentence so they should allow you to say "This store has an apple and an orange". A store could have just one apple or orange left if busineas was good... Just saying
If you just use "apel" does that mean just one apple? and if you want to say a lot of apples would you say "banyak apel"?
"Apel" can be both singular and plural, if the context is obvious (like talking about oranges in a supermarket). If it not obvious, the plural is simpy "apel-apel"
say "apel" in a different kind of "e"