a train travels 290 km in 4.5 hours and 400 km in 5.5 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 = 290 + 400 = 690 km thus , total speed = 10 hrs or , average speed = 690 / 10 or , 69 kmph . answer : b"
divide(add(290, 400), add(4.5, 5.5))