Question

Let A = {x: 2≤ x< 9 , x ∈ N} and B = { x: x is prime , x<10}

Find (i) A U B and (ii) A ∩ B
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Answer 1

Answer:

(i) A U B = {2, 3, 4, 5, 6, 7, 8}

(ii) A ∩ B = {2, 3, 5, 7}

STEP-BY-STEP EXPLANATION:

For solving this question, we first write A and B in roster form so that we can easily see the numbers.

★ According to the Question,

• For Set A

Write the numbers from 2 to 9 including 2 but excluding 9.

So, A = {2, 3, 4, 5, 6, 7, 8}

• For Set B

Write prime numbers which are less than 10.

So, B = {2, 3, 5, 7}

Now, we are asked to find:

1. A U B
2. A ∩ B

For finding A U B:

A U B includes all the terms in A and B only once.

Hence, A U B = {2, 3, 4, 5, 6, 7, 8}

For finding A ∩ B:

A ∩ B includes the terms that are common in both A and B.

Hence, A ∩ B = {2, 3, 5, 7}

Answer 2

QuEsTiOn,

Let A = {x: 2≤ x< 9 , x ∈ N} and B = { x: x is prime , x<10}

To FiNd,

$\pink{ \sf \: (i) A U B \: and } \\ \pink{ \sf \: { (ii) A ∩ B}} \: \: \: \: \:$

SoLuTiOn,

$\pink{ \sf \: Let's}$

$\green{ \sf \: We \: first \: write \: A \: and \: }$

$\pink{ \sf \: B \: in \: roster \: form}$

$\green{ \sf \: So, }$

$\pink{ \sf \: That \: we \: can \: easily \: see \: the \: </p><p>numbers.}$

$\blue{ \sf \: ★Given \: in \: Question,}$

$\green{ \sf \: For \: Set \: A }$

Write the numbers from 2 to 9 including 2 but excluding 9.

$\pink{ \sf \: So, A = (2, 3, 4, 5, 6, 7, 8)}$

$\green{ \sf \: For \: Set \: B }$

Write prime numbers which are less than 10.

$\pink{ \sf \: So, B=(2, 3, 5, 7)}$

$\blue{ \sf \:Now, we \: are \: asked \: to \: find:}$

$\green{ \sf \: (i) A U B \: } \\ \: \: \: \green{ \sf \: { (ii) A ∩ B}} \: \:$

$\pink{ \sf \: For \: finding \: A U B:}$

A U B includes all the terms in A and B only once.

$\green{ \sf \: A U B = {2, 3, 4, 5, 6, 7, 8}}$

$\pink{ \sf \: For \: finding \: A ∩ B:}$

A ∩ B includes the terms that are common in both A and B.

$\green{ \sf \: A ∩ B = {2, 3, 5, 7}}$

FiNal AnSwEr,

(i) A U B=(2, 3, 4, 5, 6, 7, 8)

(ii) A ∩ n B=(2, 3, 5, 7)

❥Hope you get your AnSwEr.