Walking speed = 6 km/h Riding speed = 3 times = 18 km/h Let distance to school be x km Time taken to walk to school = x/6 hours (because time = distance / speed) Time taken to ride back = x/18 hours Total time is given to be 1 hour So we get the equationSimplifying km Distance to school is 4.5 km Since she walked at 6 kph, how much time did she spend walking? it is Distance / speed = 4.5/6 = 0.75 hours or 45 minutes. :)