SOLUTION: Suppose Set B contains 69 elements and the total number elements in either Set A or Set B is 107. If the Sets A and B have 13 elements in common, how many elements are contained in

Algebra ->  sets and operations -> SOLUTION: Suppose Set B contains 69 elements and the total number elements in either Set A or Set B is 107. If the Sets A and B have 13 elements in common, how many elements are contained in      Log On


   

Question 1050563: Suppose Set B contains 69 elements and the total number elements in either Set A or Set B is 107. If the Sets A and B have 13 elements in common, how many elements are contained in set A?
The answer I have is 138 but it's wrough please help
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

if set B+contains 69 elements, n%28B%29=69
total number elements in either Set A or+B, then n(A U B) =107

then n(A U B)-n%28B%29 =107-69=38
38 is a number of elements that are only in +A but not in (A intersection B)
since given that (A intersection B)=13, you add it to 38 and you will get n(A=38%2B13=51
check:
n(A U B) =n%28A%29+-n%28B%29-13=%2851%2B69%29-13=120-13=107