This problem is seeming impossible to solve this is all the

Solution

There are 12 speakers in phases. Now we need to find out ways that these 12 speakers can be arranged in phases. Here the question (A) is the number of phses where zeros occurs between 0 and 360. The number of cases will be 360/12 = 30 +1 =31 ways. For instance, 0,10,20; 10,20,30;,20,30,40........; and 280,290,300.

(B) There will be 31 vector diagram that shows the triangles as shown in the question.