Question 184510
To find the number of elements in the set K U J, simply add the two sets together. However, remember to subtract the number of elements in both sets (since these elements are repeated)



In other words, use this formula:


n ( K U J) = n(K) + n(J) - n(K ∩ J)



In this case, n(K)=30, n(J)=46 and n(K ∩ J) = 11. Plug these values in to get:


n ( K U J) = 30 + 46 - 11



Add


n ( K U J) = 76 - 11



Subtract

n ( K U J) = 65



So there are 65 elements in set K U J