1. There are four lights in a cycle, 73/4 = 18 ... and the rest is 1, so it is the beginning of a new cycle, and naturally it is white light.

2.A: B = 9: 8 The greatest common factor is 7, so A is 63 and B is 56.

3. When we first met, two cars ran 1 lap, and the second car ran 60 kilometers; At the second meeting, the two cars ran three times, and the second car ran 1 time, 40 kilometers. Both cars are driving at a constant speed, so 1 circle 40 km is three times as long as 60 km, so 1 circle is 140 km.

Answer finished, hope to adopt!