A and B start from AB and meet at 90km away from a, then arrive at the destination at the same speed, return from the original road, and meet at 50km away from a, and ask the distance between AB and a

A and B start from AB and meet at 90km away from a, then arrive at the destination at the same speed, return from the original road, and meet at 50km away from a, and ask the distance between AB and a

This kind of problem has done a lot. Draw a line diagram to see the first encounter between Party A and Party B, a total of 1 whole journey, in which a line of 90 km, a second encounter between Party A and Party B, a total of 3 whole journey, in which a line of 2 whole journey minus 50 km, a total of 3 whole journey, the time is 3 times of a total of 1 whole journey, a line should be 90 × 3 = 270 km, that is 2

A, B two cars at the same time from A. B two opposite, a line to three seventh and B meet, a line of 30 kilometers per hour, B drive the whole journey to 7 hours
How far is the distance between the two places

When three seventh of a's line meets B, B's line is 1-3 / 7 = 4 / 7
While B takes 7 hours to complete the whole journey, the time they meet is 7 * 4 / 7 = 4 hours
Therefore, a line of 30 * 4 = 120 km
The distance between a and B is 120 △ 3 / 7 = 280 km

A and B start from a and B at the same time and travel in opposite directions. It takes 5 hours for a to complete the whole journey and 7 hours for B to complete the whole journey. The two cars meet in a few hours

1 / (1 / 5 + 1 / 7) = 35 / 12 hours

A and B start from a and B at the same time and travel in opposite directions. The two vehicles meet at a distance of 30 km from the midpoint. It takes 10 hours for a to complete the whole journey and 15 hours for B to complete the journey
How many kilometers are there between a and B?
Please write in detail, I am a person with a dead mind, and a question is not clear, you have to know in detail, or you don't understand (⊙ o ⊙)

It takes 10 hours for a to finish the whole journey, so the speed of a is 1 / 10, and that of B is 15 hours, so the speed of B is 1 / 15. When a and B meet, the distance of a is 2 more than that of B, 30 kilometers, that is 60 kilometers. Speed and distance are in inverse proportion. Speed of a: speed of B = distance of B: distance of a: speed of a: speed of a: speed of B: speed of a: speed of a: speed of a: speed of B: speed of a: speed of a: 1 / 10:1