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The speed of the car on the flat road, uphill road and downhill road is 30km / h, 28km / h and 35km / 1H respectively. The distance between a and B is 142km. It takes 4.5H for the car to go from a to B, 4.7H for the car to return from B. how many kilometers are there on the flat road, uphill road and downhill road?
If the uphill road and downhill road from land a to land B are x and Y kilometers respectively, they are:
x/28+y/35+(142-x-y)/30=4.5,
On the return journey, the uphill changes to downhill, and the downhill changes to uphill
x/35+y/28+(142-x-y)/30=4.7,
Just solve the equations
I'm very lazy to do my homework recently, so I don't want to calculate. Please do it by yourself and practice it by the way
A and B ride bicycles from two places 30 km apart and meet each other in one hour. If a walks 2 km more per hour than B, B's speed is ()
A and B ride bicycles from two places 30 km apart and meet each other in 1 hour. If a walks 2 km more per hour than B, B's speed is (14 km / h)
The distance between the two places is 30km. The price is from a to C, B from B to C, and a is behind. The speed is 30km per hour
B's speed is 45 kilometers per hour. If we start at the same time, a will catch up with B in a few hours
Let x hour a catch up with B
（45-30）x=30
15x=30
x=2
Xinghua village has a desert area of 30km square meters. It was originally planned to harness an area of AKM square meters every year. Later, it will harness an area of 2km square meters more than the original plan. In this way, it can be completed several years in advance
It used to take 30 years
Now it will take 30 / (a + 2) years
Therefore, it can advance 30 / a - 30 / (a + 2) = 60 / [a (a + 2)] years
Welcome to mention it again
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