Concept:?Speed:Speed is considered as the distance travelled per unit of time.Speed=distance traveled/time elapsed.Distance:Distance is defined as the length of the space between two particular points.Average:When from a list of numbers, a single number is taken as representative, then the sum of the numbers is divided by how many numbers are present in the list.It means equaling an arithmetic mean.Explanation:Given:The distance between Trivandrum and Gandhidham is = 2268 kilometres.A train covers this distance in 42 hours.Formula:Average Speed = (Total distance)/(Total Time).Calculation:Hare the total distance = 2268 km.The total time to cover the distance is = 42 hours.According to the question.Average speed= (2268) / (42).? 54 km/hour.Conversion of kilometre/hour to meter/sec1 km = 1000 meter and 1hour=3600 sec? 1000/3600? 5/18Conversion of meter/sec to kilometer/hour1 meter = 1/1000 km 1sec = 1/3600 hr? 1m/1s = 1/1000 km÷1/3600s? 3600 km/1000 s = 18km/5sConversion of unit ? a km/h =(a*1000m)/3600s.? (5a/18) m/sec.Hare, a = 54.Average speed in m/sec ? 54 À” (5/18) = 15m/sec.Thus, the average speed of the train between the railway stations of these two cities in metres per second is 15.Confusion PointsThis is a CTET 1st January, 2022 question.In English medium of the question paper the fourth option was given as 15 and in Hindi medium of the paper the fourth option was given as 25.