A car runs one third of the distance on a straight road at the speed of V1 = 40km / h, and then runs the whole distance at the speed of V2 = 20km / h Seek the average speed of the whole process

A car runs one third of the distance on a straight road at the speed of V1 = 40km / h, and then runs the whole distance at the speed of V2 = 20km / h Seek the average speed of the whole process

If the total length s is set first, the first one third of the time (1 / 3S) / 40 and the last one (2 / 3) / 20 will be used, and the total length s / 24 will be shared, then the average speed is equal to the total length and the division time is equal to 24km / h

A car is driving along a straight road, first passing through the first 13 displacements with V1, then passing through the remaining 23 displacements with V2 = 50km / h. If the average speed in the whole displacement is 37.5km/h, what is the speed in the first displacement? What is the ratio of the time taken for the first and second displacement?

The first 13 routes: X3 = v1t1 ① After 23 journey: 23x = v2t2 ② Whole course: x = V (T1 + T2) ③ The simultaneous solution is: V1 = vv23v2 − 2V = 37.5 × 503 × 50 − 2 × 37.5 = 25km / ht1: T2 = 13v1:23v2 = 13 × 25:23 × 50 = 1:1 A: the velocity in the first displacement is 25km / h, and the time ratio between the front and back displacement is 1:1

When car a and car B pass through the same displacement along the straight road, car a moves at the speed of V1 = 40km / h in the first half of the displacement and V2 = 60km / h in the second half of the displacement; car B moves at the speed of V1 = 40km / h in the first half and V2 = 60km / h in the second half of the displacement, the relationship between the average speed of car a and car B in the whole displacement is ()
A. V a = V B. v a ＞ V B C. v a ＜ v b D

V a = x 2v1 + X 2v2 = 48km / h. v b = V 1t 2 + V 2T = 50km / h. so v a < V B. so a, B and D are wrong, C is right. So C is chosen

A and B vehicles leave 360km away from each other. It is known that a's speed is 60km / h and B's speed is 40km / h. If a vehicle drives for one hour first, how long does it take for B vehicle to meet each other? (using equation solution)

Let's say the two cars meet after X hours
There are
60*X+40*X+60*1=360
100X=360-60=300
X = 3 hours