Question

in ito n(A) = 3, n(B) =5
n(AUB)=7 then findn(A-B),and
n (B-A)​

Answer 1

Given:

☛ n(A) = 3

☛ n(B) = 5

☛ n(A ∪ B) = 7

To Find:

☛ n(A - B)

☛ n(B - A)

Solution:

We know,

➜ n(A ∪ B) = n(A) + n(B) - n(A ⋂ B)

☛ 7 = 3 + 5 - n(A ⋂ B)

☛ n(A ⋂ B) = 1 ...(1)

➜ n(A - B) = n(A) - n(A ⋂ B)

☛ n(A -B) = 3 - 1 { from(1) }

☛ n(A - B) = 2

Also,

➜ n(B - A) = n(B) - n(A ⋂ B)

☛ n(B - A) = 5 - 1

☛ n(B - A) = 4

Answer 2

Answer:

n(A) +n(B)-n(AUB)

3+5-7

8-7

1