Question

Assertion: If two lines AB and CD intersect at O, such that ∠AOC = 40°, then ∠BOC = 140°.

Reason: If two straight lines intersect each other, then vertically-opposite angles are equal.
(a) Both Assertion and Reason are true and Reason is a correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not a correct explanation of Assertion.
(c) Assertion is true and Reason is false.
(d) Assertion is false and Reason is true.

Answer 1

(b) Both Assertion and Reason are true but Reason is not a correct explanation of Assertion.

Assertion:
$$\begin{gathered} \angle AOC+\angle BOC=180°\left[\because AOB\text{is a straight line}\right] \\ \Rightarrow 40°+\angle BOC=180° \\ \Rightarrow \angle BOC=140° \end{gathered}$$
Hence, the Assertion is true.
Reason:
Clearly, the given statement is true.
Hence, both the Assertion and Reason are true but Reason is not a correct explanation of Assertion.