Let A= {1, 2, {3, 4}, 5}. Which of the following statements are incorrect and why? (i) {{3, 4}} ⊂ A (ii) 1 ∈ A

Solution:

Provided that A= {1, 2, {3, 4}, 5}

(i) {{3, 4}} ⊂ A is correct

{3, 4} ∈ {{3, 4}} and {3, 4} ∈ A.

(ii) 1∈A is correct

1 is an element of A.