It takes 50 seconds for a 1000m bridge and 70 seconds for a 1500m bridge. If the speed of the train is reduced by 20%, how much does it take for the train to pass through the 1950m long tunnel [solve with the equation of one variable and one degree]

It takes 50 seconds for a 1000m bridge and 70 seconds for a 1500m bridge. If the speed of the train is reduced by 20%, how much does it take for the train to pass through the 1950m long tunnel [solve with the equation of one variable and one degree]

Let the length of train be x meters, then (1000 + x) △ 50 = (1500 + x) △ 70, the solution is x = 250250 (1 + 20%) = 300 (M / s) 1950 △ 300 = 6.5 (seconds) the train passes through the tunnel in 6.5 seconds

A train passed the 1200 meter bridge. It took just one minute from the front of the train to the rear of the train to leave the bridge, while it took 12 seconds for the train to pass the soldiers at the bridge______ Meter, speed is______ ．

1 minute = 60 seconds, train speed per second: 1200 △ 60-12, = 1200 △ 48, = 25 meters; length of the train: 12 × 25 = 300 meters; answer: the length of the train is 300 meters, the speed is 25 meters / second. So the answer is: 300; 25 meters / second

How many minutes does it take for a train with a total length of 1000 meters to cross a 5000 meter long bridge at a speed of 1500 meters per minute from the front to the rear?

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