Question

n(A)=13
n(A (intersects) B)=8
n(A U B)=20
Find n(B)=

Answer 1

\[n(A\cup B)=n(A)+n(B)-n(A\cap B)\]

Answer 2

plug your numbers in and solve

Answer 3

I don't have B though what do I do?

Answer 4

\[n(A\cup B)=n(A)+n(B)-n(A\cap B)\]
\[20=13+n(B)-8\]


solve

Answer 5

so 15 is the answer?

Answer 6

I think the answer is 4. not sure
20 = 13 + n(b) - 8
20 = 13 - 8 n(b)
20 = 5 + n(b)
20/5 = n(b)

Answer 7

@kpcoco

Answer 8

15 is correct

Answer 9

@zarkon how did u do that.

Answer 10

solve for N(B)

20=13+n(B)-8
20-13+8=n(B)
15=n(B)