The distance between a and B is 930 km, and they are running in opposite directions. A is 80 km / h, B is 90 km / h, and B's car is delayed for one hour How long does it take from departure to meeting?

Let's meet in X hours
80x+90(x-1)=930
170x=1020
x=6
From start to meet, we meet in 6 hours
Arithmetic solution
（930+90）÷（80+90）=6

A and B run from a and B, which are 20 kilometers apart. A runs 80 kilometers per hour, which is twice the speed of B. how many kilometers is the distance between the two vehicles five hours after they leave?

20 + (80 + 80 △ 2) × 5 = 20 + (80 + 40) × 5 = 20 + 120 × 5 = 20 + 600 = 620 (km). A: the distance between the two vehicles is 620 km after 5 hours

It takes 4.5 hours for a bus to travel 100km / h between two cities and 80km / h when returning

Let the distance be x kilometers
It takes X / 100 hours to go and X / 80 hours to come back
So x / 100 + X / 80 = 4.5
x(1/100+1/80)=4.5
x*9/400=4.5
x=200
So the distance is 200 kilometers

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1. A and B run from ab at the same time. B runs 1 / 20 of the whole journey per hour more than a, and the two cars run 9 / 20 of the whole journey per hour. They go on after meeting for the first time on the way. A goes to B, B returns to a immediately, and they meet again on the way. If the two cars meet 40 kilometers apart

The distance between a and B is 930 km, and they are running in opposite directions. A is 80 km / h, B is 90 km / h, and B's car is delayed for one hour How long does it take from departure to meeting?