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1. Party A and Party B ride bicycles from two places 65km apart at the same time. After two hours, Party A and Party B meet. Party A rides 2.5km more per hour than Party B. find out the speed of Party B 2. A passenger's train is moving at a speed of 40km / h. he sees the oncoming train passing by him in 3S. It is known that the oncoming train is 75m long. Find the speed of the oncoming train. (train equation solution) 3. A and B practice the 100m race. A runs 7m per second and B runs 6.5m per second. If a asks B to run for 1s first, a can catch up with B in a few seconds 4. Both Party A and Party B go from place a to place B. Party A walks 5km per hour, 1.5h first; Party B rides a bicycle, and Party B walks for 50min. They arrive at the destination at the same time, and ask Party B how many kilometers per hour 5. The distance between the enemy and us is 28km. We know that the enemy fled at the speed of 8km per hour one hour ago. Now our army is chasing the enemy at the speed of 14km per hour, and can catch up with the enemy in a few hours
one
If the velocity of B is XKM / h, then the velocity of a is (x + 2.5) km / h, then:
2X + 2 (x + 2.5) = 65 to get x = 15km / h
two
Let the speed of the opposite train be x m / s, and the speed of the train is 40 km / h, that is 100 / 9 m / s
So: (x + 100 / 9) * 3 = 75, x = 125 / 9 m / s, i.e. 50 km / h
three
Suppose that after x seconds, a can catch up with B. when they catch up, they run the same distance
6.5 * (x + 1) = 7 * x, the solution is x = 13 seconds
four
Suppose that the speed of B is XKM / h and the distance is equal, then:
5 * (1.5 + 50 / 60) = (50 / 60) * x = 14km / h
five
If you catch up with the enemy in X hours, then:
14 * x = 8 * x + 28 + 8, x = 6 hours
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