Question

:) If n(A - B) = 23. n(B - A) = 18 and n(AnB) = 7. then
find n(AUB) (2)​

Answer 1

Given

• n(A - B) = 23

• n(B - A) = 18

• n(A ∩ B) = 7

To find

• n(A U B)

Solution

* Using the operation :

✓ n(A - B) = n(A) - n(A ∩ B)

➺ 23 = n(A) - 7

➺ n(A) = 30

✓ n(B - A) = n(B) - n(A ∩ B)

➺ 18 = n(B) - 7

➺ n(B) = 25

✓ n(A U B) = n(A) + n(B) - n(A ∩ B)

➺ n(A U B) = 30 + 25 - 7

➺ n(A U B) = 48 (Answer)