a train travels 210 km in 3 hours and 270 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 = 210 + 270 = 480 km thus , total speed = 7 hrs or , average speed = 480 / 7 or , 69 kmph . answer : b"
divide(add(210, 270), add(3, 4))