The bus and the truck leave from a and B at the same time. After 4 hours, the two cars meet on the way. After meeting, the bus takes 3 hours to reach B. how many hours does it take for the truck to get from B to a?

The bus and the truck leave from a and B at the same time. After 4 hours, the two cars meet on the way. After meeting, the bus takes 3 hours to reach B. how many hours does it take for the truck to get from B to a?

If the distance between the two places is x km, the whole journey of the bus takes 7 hours, the speed of the bus is VK = x / 7, the 4-hour journey of the bus is VK * 4 = 4x / 7, then the 4-hour journey of the truck is x-4x / 7 = 3x / 7, the speed of the truck is VH = distance △ time = (3x / 7) △ 4 = 3x / 28, the truck has traveled 3x / 7 km in 4 hours from place B to place a, and there is still 4x / 7 left

A freight car and a passenger car leave from station a and station B at the same time. After 9 hours of meeting, the two cars continue to move forward at the same speed. It is known that the freight car arrived at station B after another 6 hours. How many hours does it take for the passenger car to complete the whole journey?

The passenger car and the freight car are facing each other at the same time. They meet in 9 hours and travel 1 / 9 of the whole journey per hour. This is the sum of the speed of the passenger car and the freight car. The complete journey of the freight car takes (9 + 6) hours and 1 / 15 of the whole journey per hour. The speed of the passenger car is calculated by subtracting the speed of the freight car from the speed of the freight car. Dividing 1 by the speed of the passenger car is the time it takes for the passenger car to complete the whole journey
9 + 6 = 15 (hours)
1 / 9-1 / 15 = 2 / 45 freight car speed
1 / (2 / 45) = 24.5 hours for trucks to complete the whole journey

(additional question) the passenger car and the freight car leave each other at the same time from station a and B, and they meet five hours later. After meeting, the two cars still move at the original speed. When they are 196 km apart, the passenger car runs 35% of the whole journey and the freight car runs 80% of the whole journey. (1) how many kilometers is the whole journey? (2) How many hours does it take for the truck to complete the whole journey?

(1) 196 (35 + 80% - 1), = 196 (0.6 + 0.8-1), = 196 (0.4), = 490 (km); answer: the whole journey is 490 km. (2) the passenger cargo speed ratio is 35:80% = 3:4; then the freight car speed is (490 △ 5) × 43 + 4, = 98 × 47, = 56 (km); the time required for the freight car to complete the whole journey is 490 (hours). Answer: the whole journey takes 834 hours for the freight car

On the map marked, it is measured that the distance between a and B is 12% water. A passenger car and a freight car start from a and B at the same time and travel in opposite directions. After 4 hours, they meet. The speed ratio of the passenger car to the freight car is 7:5. How many kilometers does the freight car travel per hour?

According to the scale, the distance of 1cm on the map represents the actual distance of 80km. The actual distance between a and B: 12 × 80 = 960km. The speed of freight cars: 960 △ 4 × 57 + 5 = 240 × 512 = 100km. A: the speed of freight cars is 100km per hour