This task is stumped Australian high school students

Australian high school students during a national testing tossed task of geometry, put most of the students in a deadlock. In social networks rose Bucha: they say, why make such mozgolomnye job in the exam. And you little to solve?





Condition:

50 cents coin has facets 12 of equal length. Two coins put close to each other on a table as shown in the picture.





We need to find the angle X