A boy goes to school with a speed of 75 km/h and comes back with a speed of 45 km/h. find his average speed?
Since the distance travelled by a boy (going to school and coming back from school) is equal. So, average speed = 2xy/(x + y) Average speed = (2 x 75 x 45)/(75 + 45) Average speed = (2 x 75 x 45)/120 = 56.25 km/hr
