Q155 / 270 · NDA 2019 (Phase 1) · Mathematics
Consider the following statements for the two non-empty sets $A$ and $B$ :
(1) $(\mathrm{A} \cap \mathrm{B}) \cup(\mathrm{A} \cap \overline{\mathrm{B}}) \cup(\overline{\mathrm{A}} \cap \mathrm{B})=\mathrm{A} \cap \mathrm{B}$
(2) $(\mathrm{A} \cup(\overline{\mathrm{A}} \cap \overline{\mathrm{B}}))=\mathrm{A} \cup \mathrm{B}$
Which of the above statements is/are correct ?
- A1 only
- B2 only
- CBoth 1 and 2
- Correct answerDNeither 1 nor 2
Solution
1. $(A \cap B) \cup(A \cap \bar{B}) \cup(\bar{A} \cap B)=A \cup B$
Let us draw Venn diagram.

$\therefore 1$ is correct. 2. $A \cup(\bar{A} \cap \bar{B})=A$
$\therefore 2$ is not correct. Correct option (1).

$\therefore 1$ is correct. 2. $A \cup(\bar{A} \cap \bar{B})=A$

$\therefore 2$ is not correct. Correct option (1).
Hence, the correct answer is option: 'D'.