Passenger and freight cars leave from the two places at the same time. After three hours, they meet. Passenger cars travel 72 kilometers per hour and freight cars 78 kilometers per hour. How many kilometers are there between the two places

Passenger and freight cars leave from the two places at the same time. After three hours, they meet. Passenger cars travel 72 kilometers per hour and freight cars 78 kilometers per hour. How many kilometers are there between the two places

According to distance = speed × time, there is
72 × 3 + 78 × 3 = 450 (km)
A: (omitted)
To transport a batch of goods, it takes 8 hours for car a and 12 hours for car B. car a transports for 3 hours first, and then car a and car B transport together. How many hours will it take?
To build a section of highway, it takes 6 days for Party A and Party B to build it together, and 10 days for Party A to build it alone?
Party A and Party B process a batch of parts. Party A will finish the work in 8 hours, Party B will finish the work in 10 hours, Party A will finish the work in 2 hours, and then work together with Party B. how many more hours?
Two engineering teams jointly build a 324 km canal, which will be completed in 27 days. One team builds 5 km per day on average, and the two teams build more kilometers per day on average?
Four people can load 48 bicycles in six hours. Now it's required that 112 bicycles be built in eight hours. How many more people are needed?
For a project, 15 workers are planned to work 4 hours a day and complete it in 18 days. If three workers are added and the working hours are increased by one hour, how many days will it take to complete the task?
1. (1-3 / 8) / (1 / 8 + 1 / 12) = 3 hours 2, (1-4 / 6) / (1 / 6-1 / 10) = 3 days 3, (1-2 / 8) / (1 / 8 + 1 / 10) = 10 / 3 hours 4. This feeling is a bit ambiguous. If the two teams average more training every day: 324 / 27 = 12 kilometers, if the two teams average daily training should be 12-5 = 7 kilometers 5, 4 people 6 hours
(H-1/8H*3)/(1/8H+1/12H)
Two piles of the same amount of coal, the first pile uses 3 / 4 of it, the second pile uses 3 / 4 tons, the rest of the coal
1. Weight of the first pile
2. The second pile is heavy
3. The same weight
4. Can't be sure
Four
Because it's two piles of the same amount of coal, suppose there are 100 tons each: the first team uses 3 / 4 of 100
100 × 3 / 4 = 75 (tons) this is the rest of the first team. The second team's 3 / 4 tons is 0.75 tons,
75-100 tons. 75 < 99.25, so choose 2: the second pile weight.
At the same time, passenger cars and freight cars depart from a and B. passenger cars travel 78 kilometers per hour and freight cars 72 kilometers per hour. When they meet, passenger cars travel 18 kilometers more than freight cars
How many kilometers are there between B and a?
Passenger cars and freight cars leave from a and B at the same time. Passenger cars travel 78 kilometers per hour and freight cars 72 kilometers per hour. When they meet, passenger cars travel 18 kilometers more than freight cars. How many kilometers are there between a and B?
78-72 = 6 (km) ---- this is an extra 6 km per hour
18 △ 6 = 3 (hours) --- the time they met
(78 + 72) × 3 = 450 (km) ---- this is the common road to meet
A: A and B are 450 kilometers apart
Even if it is calculated according to the distance traveled by passenger cars - the distance traveled by freight cars = 18 km, the time should be calculated first. The specific solution is
The bus and truck have been running for X hours
78x－72x=18
6x =18
x =3
The total distance is:
78 × 3 + 72 × 3 = 150 × 3 = 450 (km) of course, the latter solution can drag it to the above sentence, which is: suppose that the passenger cars and freight cars have driven for X hours, then the total distance is (78
Even if it is calculated according to the distance traveled by passenger cars - the distance traveled by freight cars = 18 km, the time should be calculated first. The specific solution is
The bus and truck have been running for X hours
78x－72x=18
6x =18
x =3
The total distance is:
78 × 3 + 72 × 3 = 150 × 3 = 450 (km) of course, the latter solution can drag it to the above sentence, that is: if the passenger cars and freight cars have been running for X hours, the total distance is (78x + 72x) km
A: the distance between a and B is 450 km. Put it away
It takes 8 hours to transport a batch of goods at the same time. It takes 24 hours to transport a batch of goods by car a alone. Now, it takes 18 hours to transport the remaining goods by car B after several hours by car a alone. Question: how many hours did car a and car B deliver each?
First calculate the completion time of vehicle B: Set: the completion time of vehicle B is x hours
8 / 24 + 8 / x = 1 multiply both sides by 24 and X to get 8x + 192 = 24x
16x = 192 x = 12 (hours) B completed 12 hours alone;
Then calculate the respective transport hours: suppose: vehicle a transport x hours, vehicle B transport (18 - x) hours
X / 24 + (18-x) / 12 = 1 multiply both sides by 24 to get x + 36-2x = 24
2x-x = 36-24 x = 12 hours (a) 18-12 = 6 hours (b)
Checking: 12 / 24 + 6 / 12 = 1 / 2 + 1 / 2 = 1
Note: in mathematical problems like this, the goods are counted as integer 1
There are two piles of coal. The weight of the first pile is 2 / 3 of the two piles. After the first pile uses 1 / 4, it is 1 / 2 tons more than the second pile. How many tons is the first pile? What about the second pile?
X is the weight of the first pile
The weight of the second pile is expressed as the weight of the second pile
x=(x+y)*2/3
x*3/4-y=1/2
The solution is as follows
X=2
Y=1
The passenger and freight cars leave each other from the two places. The passenger car travels 50 kilometers per hour, and the freight car 65 kilometers per hour. When the freight car reaches the middle, it will travel with the passenger car
It's 75 kilometers away. The distance between a and B is calculated
When the truck goes to the middle, the time is as follows:
75 ÷ (65-50) = 5 hours
Distance between a and B:
65 × 5 × 2 = 650 km
How long does it take for a truck to reach the middle
75 (65-50) = 5 (hours)
What is the distance between a and B
65 × 5 × 2 = 650 (km)
The transport team has to carry 72 tons of goods. 16 trucks have been carried away, and there is still one ninth of them not moving. How many tons of goods are carried by each truck?
Good luck
72-72x1/9
=72-8
=64 tons
Per car
64 △ 16 = 4 tons
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In the second pile, there are two piles of coal, each of which has three tons more than the first pile______ 、______ Tons
Let the second pile weigh x tons, the first pile weigh (x + 50) tons, x + 50-75 = (x-75) × 3, x + 50-75 = 3x-225, & nbsp; & nbsp; & nbsp; & nbsp; 2x = 200, & nbsp; & nbsp; 2x △ 2 = 200 △ 2, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 100, the first pile weigh 100 + 50 = 150 (tons)
The distance between a and B is 360 km. The passenger and freight cars run from each other at the same time. After 2.5 hours, the two cars meet. The passenger car runs 60 km per hour and the freight car runs 60 km per hour
How many kilometers per hour?
Solve by equation
Set up freight cars to travel x kilometers per hour
（x+60）*2.5=360
x+60=144
x=84