# Noun following a list of like items - plural or singular?

If you have a list of descriptors (probably names or colours, but could be other things) which refer to items of the same type, followed by a noun which applies to all of the items in the list, should that noun be plural or singular?

For example:

"If you choose the red, yellow or blue door/doors, then you win a prize."

"If you operate the 'On' or 'Activate' switch/switches, the machine will operate normally."

If neither is wrong, but it depends on the context, what does the plural/singular imply about the items in the list? For example if there is only 1 each of the red, yellow and blue doors (vs if there are 2+ of each colour) does that affect which noun should be used?

My inclination was that the noun should be pluralised as it refers to multiple items (there are multiple doors, multiple switches) however I can see the argument that if there is only one blue door, one yellow door, etc. then 'door' should remain singular.

Thanks!

• Look at the expanded forms: "If you choose the red door, the yellow door, or the blue door, then you win a prize." / "If you choose the red door, the yellow doors, or the blue door, then you win a prize." (you can't delete this one) etc. Commented Oct 3, 2016 at 21:58
• Thanks. Good point about expanding. I considered this but wasn't sure how to do so. Your example makes it obvious. So if everything on the list is singular, you would use the singular. If everything is plural, you use the plural. If there is a mixture then you would presumably either use the plural, or whatever applies to the item listed last. If we are the reader, we can infer the quantities of the items in the list from the type of noun used. door = 1 of each type. doors = 2+ of at least one type. And if we intend the choice to be exclusive? Use 'a (X or Y) door' instead of 'the'? Commented Oct 5, 2016 at 9:25
• I think you're forced to rewrite more fully unless (1) there is one door of each colour or (2) you are choosing a colour-coded set of doors. Thus "If you choose the red door, either of the yellow doors, or one of the blue doors, then you win a prize." Commented Oct 5, 2016 at 17:33