n(AuB) if a = 2,3,4 and b = 3,5,7

Question

i want to know the mean of the above equation.. 

 

Answer 1

n(AuB)

 

The n() means that we're counting how many elements are in the set between the parentheses.

 

AUB is every element in both sets. Let's first add every element in A

 

AUB = {2, 3, 4}

 

Next, let's add the elements in B that are not already in the set:

 

AUB = {2, 3, 4, 5, 7}

 

There are 5 elements in this set, so n(AUB) = 5