First, let's state the given information:
The number of donors with the blood of type O+ is 6.
The number of donors with the blood of type A+ is 4.
The number of donors with the blood of type B+ is 2.
we will label these numbers as follows for reference:

We will also need the total number of donors "n":

Since we are asked to find the distinguishable ways in which the donors can be in line, we need to find the number of permutations.
The formula for permutations is:

Where "!" means factorial, and is defined as follows, for example, 4! is:

And so on depending on the number.
In this case, the operation we have to solve is:

Solving this division we get the result for the number of distinguishable ways in which the donors can be in line:

Answer: 13,860