00:03
Hi, thank you so much for your question.
00:05
So, a union b union c equals a plus b plus c, minus a intersects b, a intersects c, minus b intersects c, plus a intersects b intersects c, okay? so, a intersects c equals b.
01:01
A intersects b equals b intersects c equals 4.
01:18
So, if a, b, and c contain, respectively, with 12, 8 and 11 elements.
01:25
So here is 12, 8, 11.
01:31
And if their union, a union, b union, c contains 16 elements, so how many elements that their intersection a intersects b intersects c contains? so that is the question, okay? so a intersects c is 8.
01:49
A intersects b is 4 and this is 4...