If the speed of a car from city a to city B is increased by 20%, it can arrive at city B one hour earlier than the original time; if the speed is increased by 30% after driving 100 km at the original speed, it can arrive at city B one hour earlier than the original time______ Kilometers

If the speed of a car from city a to city B is increased by 20%, it can arrive at city B one hour earlier than the original time; if the speed is increased by 30% after driving 100 km at the original speed, it can arrive at city B one hour earlier than the original time______ Kilometers

The ratio of the original speed to the increased speed is 1: (1 + 20%) = 5:6, so the ratio of time spent on the same journey is 6:5. The original time needed to reach the second place is: 6 × [1 ÷ (6-5)] = 6 × [1 ÷ 1] = 6 × 1 = 6 (hours). After driving 100 km, the ratio of driving speed to the increased speed is 1: (1 + 30%) = 10:13, so the ratio of time spent on the same journey is 1: (1 + 30%) = 10:13 The ratio is 13:10, so the journey after 100 km takes 13 × [1 △ 13-10] = 13 × [1 △ 3] = 13 × 13 = 133 (hours) and the journey before 100 km takes 6-133 = 53 (hours). The journey between the two places takes 100 △ 53 × 6 = 60 × 6 = 360 (kilometers). A: the distance between a and B is 360 km. So the answer is: 360 km