Let `A={1,{2}, {3, 4}, 5}`. Which of the following are incorrect statements? Rectify each : (i) `2 in A` (ii) ` {2} sub A` (iii) ` {1,2 } sub A` (iv) `{3, 4 } sub A ` (v) ` {1,5} sub A` (vi) ` {phi} sub A ` (vii) ` 1 sub A ` (viii) `{1,2,3,4 } sub A `.

Let `A={1,{2}, {3, 4}, 5}`. Which of the following are incorrect state

1.	Let `A={1,{2}, {3, 4}, 5}`. Which of the following are incorrect statements? Rectify each : (i) `2 in A` (ii) ` {2} sub A` (iii) ` {1,2 } sub A` (iv) `{3, 4 } sub A ` (v) ` {1,5} sub A` (vi) ` {phi} sub A ` (vii) ` 1 sub A ` (viii) `{1,2,3,4 } sub A `.
Answer» Clearly, A contains four elements, namely `1, {2} , {3,4 } and 5` (i) `2 in A` is incorrect. The correct statement would be `{2} in A`. (ii) `{2} sub A ` is incorrect. The correct statement is ` {{2}} sub A`. (iii) Clearly, `2 lin A ` and therefore , ` {1, 2 } sub A` is correct. THe correct statement would be `{1,{2},} sub A`. (iv) Clearly, `{3,4}` is an element of A. So, ` {3,4}, sub A` is incorrect and ` {{ 3,4}} sub A ` is correct. (v) Since 1 and 5 are both elements of A, so `{1,5} sub A` is correct. (vi) Since ` phi lin A`, so `{phi} sub A` is incorrect while `phi sub A ` is correct. (vii) Since ` 1 in A`, so ` 1 sub A` in incorrect and therefore , `{1} sub A ` is correct. (viii) Since ` 2 lin A and 3 lin A` , so `{1,2,3,4}sub A ` is incorrect. The correct statement would be `{1,{2}, {3,4}}sub A`.