Respuesta :

Answer:

20 elements.

Step-by-step explanation:

Lets say

n(U) = 114

n(A) = 57

n(B) = 79

n(A n B)= 42

Now,

n(A U B) = n(A) + n(B) - n(A n B)

= 57 + 79 - 42

= 94

Now,

n(A U B) compliment = n(U) - n(A U B)

= 114 - 94

= 20

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