Directions for the following 3 (three) items: Consider the given information and answer the three items that follow.
Eight railway stations A, B, C, D, E, F, G and H are connected either by two-way passages or one-way passages. One-way passages are from C to A, E to G, B to F, D to H, G to C, E to C and H to G. Two-way passages are between A and E, G and B, F and D, and E and D.
If the route between G and C is closed, which one of the following stations need not be passed through while travelling from H to C?
Answer & explanation
Answer: (c) A
H's only exit is G, and with G to C closed, G must go to B, then F, then D. From D the train reaches C only through E. The route H-G-B-F-D-E-C passes E, D and B but never needs A.
- Exits from each station: A → E; B → F, G; C → A; D → H, F, E; E → G, C, A, D; F → D; G → C, B; H → G.
- H → G is the only exit from H.
- G → C is closed, so G → B; then B → F (B → G goes back) and F → D.
- From D: D → H goes back, so D → E; from E go straight to C.
- Route: H → G → B → F → D → E → C. It passes E, D and B but not A.
- A can be entered only from C or E and leads only back to E, so it is never needed.
Remember · When a link closes, trace the forced path one exit at a time; stations off that path need not be passed.
Question and answer: UPSC's official GS Paper II (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·