Question 4 Given the following definitions:
U = {1, 2, 3, 4, 5, 6, 7}
A = {1, 2, 4,5)
B = {1, 3, 5, 7)
How many elements are in A u B?

Step-by-step explanation:

Given,

U = { 1 , 2 , 3 , 4 , 5 , 6 , 7 }

A = { 1 , 2 , 4 , 5 }

B = { 1 , 3 , 5 , 7 }

Finding A union B ( A ∪ B )

A ∪ B = { 1 , 2 , 4 , 5 } ∪ { 1 , 3 , 5 , 7 }

The union of two sets A and B is the set of all elements which belongs either A or B or both A and B.

Let's list the elements :

A ∪ B = { 1 , 2 , 3 , 4 , 5 , 7 }

In the question , we are asked to find out the number of elements present in A ∪ B

Now, count the Elements:

= 6

Thus, There are 6 elements in A ∪ B

Hope I helped !

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