Question 1155136
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There are  66 + 94 - 1 = 159 elements in the union.    <U>ANSWER</U>




    Every time, when you have an universal set U and two its finite subsets A and B with  n(A) and n(B) elements 

    respectively,  the number of elements in their UNION (A U B) is

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

    where n(A intersection B) is the number of elements in their intersection.
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The last equality DESERVES you MEMORIZE it.


It is one of the basic equalities (identities) in elementary Set theory.


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See the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/misc/Counting-elements-in-sub-sets-of-a-given-finite-set.lesson>Counting elements in sub-sets of a given finite set</A>

in this site.