Article after 'and' and 'or'

Question

When talking about two objects using and and or, when should I use a and an? Take the following sentences as an example. When is the article appropriate?

1. I have an orange and apple in my hand.
   I have an orange and an apple in my hand.

2. I have a television and radio at my home.
   I have a television and a radio at my home.

3. I would love to have an orange or an apple in breakfast.
   I would love to have an orange or apple in breakfast.

4. I had some money three months ago, I could buy a television or a radio.
   I had some money three months ago, I could buy a television or radio.

5. I have a mango and an apple in my hand.
   I have an apple and mango in my hand.

Answer 1

In general, you need to repeat the article. The conjunction and or or joins two noun groups, each of which need to include an article (which can be the null article sometimes, of course).

I have an orange and an apple in my hand.
I had some money three months ago, I could buy a television or a radio.

There is an exception for and, when you are not saying that there are two objects, but that there is a single object which can be designated by two nouns. For example:

I have a washing machine and a dryer. [I have two appliances.]
I have a washing machine and dryer. [I have a single appliance which has both functions.]

This is rare, however. In this example, the standard term would be “washer-dryer”. Without using that term, other possibilities include “washing machine and dryer combination” or “washing machine cum dryer” or “washing machine with dryer”.

It is possible to have a pattern like “a NOUN1 and NOUN2 NOUN3”, where “NOUN1 and NOUN2” is a complement of NOUN3. Here NOUN1 and NOUN2 take the null article; the article a is attached to NOUN3. So the article is repeated.

I have a steak and kidney pie in the oven.
I have a steak and kidney pie and an apple strudel in the oven.

With or, you can sometimes leave out the second article. There isn't a clear difference in meaning, but leaving out the article tends to indicate that there is a given object whose nature is in doubt, whereas including the article tends to indicate that there are two objects and there is a choice between these two. It is not common to leave out the second article.

Answer 2

I'm not providing an alternative answer, but adding, for future reference (and when this answer is linked to as a previous answer to duplicate questions) that this answer applies to both definite and indefinite articles.

In other words, you can replace 'a/an' with 'the' and Gilles's answer still applies.