Curt has 12 models in all Three of the are airplanes 5 more cars than boats How many does have?

Then the number of cars is "b + 5".

And the number of airplanes is "3".

So, the total number of models is "b + (b + 5) + 3 = 2b + 8".

And given that the total number of models is "12".

2b + 8 = 12

2b = 4

b = 2

Therefore, Curt has 2 boats.