16. Find the power set of A = {{a, b}, c}.

1. 1. {ϕ, {a, b}, {c}}

   
   
   

   2. {A, {a, b}, {c}}

   
   
   

   3. {ϕ, A, {a, b}, {c}}

   
   
   

   4. None of these
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let, A = {{a, b}, c}. To determine P(A) : Since A contains two elements {a, b}, c, P(A) will contain 2² = 4 elements.
   
   

   Correct Option: C

   Let, A = {{a, b}, c}. To determine P(A) : Since A contains two elements {a, b}, c, P(A) will contain 2² = 4 elements.
   The elements of P(A) are Φ, A, {a, b}, {c}.

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17. Let A = {1, 2, {3, 4}, 5}. Which of the following statements is true?

1. 1. {3, 4} ⊂ A
      

   
   
   

   2. {3, 4} ∈ A

   
   
   

   3. 1 ⊂ A

   
   
   

   4. {1, 2, 5} ∈ A

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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18. Let A = {1, 2, {3, 4}, 5}. Which of the following statements are true?

1. 1. {3, 4} ⊂ A;

   
   
   

   2. {3, 4} ∈ A;

   
   
   

   3. {{3, 4}} ⊄ A;
      

   
   
   

   4. {1, 3, 5} ⊂ A.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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19. If A = { x : x = n-1/n+1, n ε W and n ≤ 10 } ;point out the correct statement from the following:

1. 1. 0 ∈ A

   
   
   

   2. 0 ⊂ A

   
   
   

   3. 0 ⊃ A

   
   
   

   4. 1/3 ∉ A
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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20. If U = {a, b, c, d, e, f}, A = {a, b, c}, B = {c, d, e, f}, and C = {c, d, e} find (A ∪ B) ∪ C.
    

1. 1. A

   
   
   

   2. B

   
   
   

   3. C

   
   
   

   4. U

   
   
   

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1. View Hint View Answer Discuss in Forum

   A ∪ B = { a, b, c } ∪ { c, d, e, f } = {a, b, c, d, e, f}
   
   

   Correct Option: D

   A ∪ B = { a, b, c } ∪ { c, d, e, f } = { a, b, c, d, e, f }
   ∴ (A ∪ B) ∪ C = { a, b, c, d, e, f } ∪ { c, d, e }
   = { a, b, c, d, e, f }
   = U.

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