Daily Math Puzzle: 2026-03-14

48 km/h — Many people mistakenly average the two speeds: (60 + 40) / 2 = 50 km/h. However, average speed is calculated as total distance divided by total time. This distinction is key. Let 'D' be the distance between City A and City B. 1. **Time taken for the journey from A to B:** Time = Distance / Speed = D / 60 hours. 2. **Time taken for the journey from B to A:** Time = Distance / Speed = D / 40 hours. 3. **Total distance for the round trip:** Total Distance = D (to B) + D (back to A) = 2D. 4. **Total time for the round trip:** Total Time = (D / 60) + (D / 40) To add these fractions, find a common denominator, which is 120: Total Time = (2D / 120) + (3D / 120) = 5D / 120 = D / 24 hours. 5. **Average speed for the entire round trip:** Average Speed = Total Distance / Total Time Average Speed = (2D) / (D / 24) Average Speed = 2D * (24 / D) Average Speed = 48 km/h. The distance 'D' cancels out, which means the specific distance between the cities does not affect the final average speed.