The cupcakes cook faster than the big one piece cakes, so does it make sense to assume that the cup cakes bake faster in a 24 hole cup cake tray rather than a 12 hole cup cake tray?
My oven has a convection fan.
I immediately thought of this table, from the front of the muffin section in Bread, by Beth Hensperger*:
Muffin size Baking time Yield Mini/gem (1 5/8") 10-15 minutes 18-20 Regular (2 3/4") 20-25 minutes 9-10 Oversized (3 1/4") 25-30 minutes 6-7 Muffin cake (8-9") 55-65 minutes 1
The baking times are for 375-400F; most recipes will fall around that range. Note that the yields don't necessarily match up to typical pan sizes; for example, if you take a recipe meant for 12 regular muffins, you'll probably have more batter than you need for a pan of 6 oversized muffins. Similarly, if your recipe says to bake regular muffins for 30 minutes, you might have to bake miniature ones a bit over 15 minutes. "Muffin cake" refers to baking in an 8-9" pan of some sort - the author says that you can get away with it for any muffin recipe, but I've never tried it!
P.S. I know this is for muffins, but cupcakes are fairly similar, so I think it'll be about right!
* At least, I'm pretty sure it is. I have a copy of just this page (for the recipe next to the table, actually), from a book my mom has. I recognize the cover, I know we had that book, I think this was in it, and Google book search somehow found it when I searched for "fresh-lemon muffins".
Yes, they will indeed cook faster, simply because the heat can penetrate through the cakes faster. Likewise, if you had 48 instead of 24, they would take even less time.
If the size per cake is reduced then they will bake faster and also have a greater chance of becoming dryer. If they are the same size per cake simply more of them, then no they won't bake faster and will probably take a little longer to cook.