a train travels 250 km in 2 hours and 350 km in 4 hours . find the average speed of train .
"as we know that speed = distance / time for average speed = total distance / total time taken thus , total distance = 250 + 350 = 600 km thus , total speed = 6 hrs or , average speed = 600 / 6 or , 100 kmph . answer : d"
divide(add(250, 350), add(2, 4))