On one side of a 1.01 km long road, 101 plants are planted at equal distance from each other. What is the total distance between 5 consecutive plants?
Answer & explanation
Answer: (b) 40.4 m
With plants at both ends of the road, 101 plants make 100 equal gaps along 1010 m, so each gap is 10.1 m. Five consecutive plants span 4 gaps: 4 × 10.1 = 40.4 m.
- 101 plants in a line from one end of the road to the other leave 101 − 1 = 100 gaps.
- Road length = 1.01 km = 1010 m, so each gap = 1010 ÷ 100 = 10.1 m.
- 5 consecutive plants have 4 gaps between them: 4 × 10.1 = 40.4 m.
- Trap: dividing 1010 by 101 (counting plants instead of gaps) gives 10 m and the wrong answer 40 m.
Remember · n objects in a line make n − 1 gaps; k consecutive objects span k − 1 gaps.
Question and answer: UPSC's official GS Paper II (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·