A tram overtakes 2 persons X and Y walking at an average speed of 3 km/hr and 4 km/hr in the same direction and completely passes them in 8 seconds and 9 seconds respectively. What is the length of the tram?

उत्तर देखें और व्याख्या

उत्तर: (C) 20 m

व्याख्या

(v - 3) × 8 = (v - 4) × 9 gives v = 12 km/h. Length = 9 km/h × 8 s = 2.5 m/s × 8 = 20 m. (Answer as per the official UPSC answer key.)