A Train travels 12 km in 1st 10 minutes,11 km in next 10 minutes, 8.5 km in next 10 minutes, 8.5 in next 10 minutes, 6 km in next 10 minutes.
What is the average speed of train in km/hr ?

Average speed equals the total distance travelled divided by the time it takes. Do the math and post back with your answer, and we'll check it for you.