Question

if A=(4,6,7),B=(5,7,8) then n(AUB)​

Answer 1

Answer:

n(AUB) =(4,5,6,7,8)

Step-by-step explanation:

A =(4,6,7)

B=(5,7,8)

for Union we have to take the all the elements of A and B and we have to write those elements single time only which are both in A and B.

so AUB = (4,5,6,7,8)

Answer 2

Answer:

5 → {4,5,6,7,8}

Step-by-step explanation:

Method 1

No. of elements in A = 3

No. of elements in B = 3

So, n(AUB) = 3 + 3 = 6 → {4,5,6,6,7,8}

But, since the same elements are not repeated,

Therefore, n(AUB) = 5

Method 2

n(A) = 3

n(B) = 3

n(A∩B) = 1 {7}

So, n(AUB) = n(A) + n(B) - n(A∩B)

⇒ n(AUB) = 3 + 3 - 1 = 5

Hope this helps.....