RRB NTPC Undergraduate CBT 1 4 Sept 2025 Shift 1 – Question Paper

Concept: Ishwar Chandra Vidyasagar (1820–1891) was the leading Bengal reformer for widow remarriage and women’s education.

1. His campaign led to the Hindu Widows’ Remarriage Act, 1856.
2. He helped open many girls’ schools in Bengal and worked with J.E.D. Bethune for the Bethune School.
3. Keshab Chandra Sen was a Brahmo leader (inter-caste marriages, Brahmo Marriage Act 1872); Debendranath Tagore led the Brahmo Samaj; Vivekananda founded the Ramakrishna Mission.

Yaad rakhein: Widow remarriage + Bengal = Vidyasagar (1856 Act).

Answer: (B) Ishwar Chandra Vidyasagar

Concept: Angle sum of a triangle is ${180}^{\circ }$; an exterior angle equals the sum of the two interior opposite angles.

1. In $△BDC$: $\angle BDC={90}^{\circ }$, $\angle DBC={60}^{\circ }$ ⇒ $\angle C={180}^{\circ }-{90}^{\circ }-{60}^{\circ }={30}^{\circ }$.
2. In $△AEC$: $\angle EAC={49}^{\circ }$, $\angle ECA={30}^{\circ }$.
3. $\angle AEB$ is the exterior angle of $△AEC$ at E: $\angle AEB={49}^{\circ }+{30}^{\circ }={79}^{\circ }$.

Trick: Exterior angle = sum of the two far interior angles – no need to find $\angle AEC$.

Answer: (D) ${79}^{\circ }$

Concept: Change every digit by the rule: even → +1, odd → −2.

1. 4 5 6 2 7 3 4 → 5 3 7 3 5 1 5.
2. New number: 5373515.
3. Highest digit 7, lowest 1; difference $=7-1=6$.

Trick: Write the new digits directly under the old ones to avoid mistakes.

Answer: (C) 6