Question

If set A = {3,4,7,9}, set B = {8,9,10,11}, and set C = {4,9,11,14,15}, then An(BuC) =

Answer 1

From the question, we have

A = {3, 4, 7, 9}

B = {8, 9, 10, 11}

C = {4, 9, 11, 13, 15}

To get this lets first find B union C. This is all the items found in B or C or both, but not repeated. So B union C is

`B\cup C=\lbrace4,8,9,10,11,13,15\rbrace`

Now A intersection B union C are the elements common to set A and set B union C. We have

`A\cap(B\cup C)=\lbrace4,9\rbrace`

Hence the first option is the answer