Question

A train of length 120 m, travelling at 30 m/s takes
30 s to overtake another train of length 240 m. If
both the trains are travelling in the same direction,
then find the speed of the longer train.​

Answer 1

Answer:

speed of the longer time will be 18 metre per second

Answer 2

Given:

✭ Length of shorter train = 120 m

✭ Speed of shorter train = 30 m/s

✭ Time taken by short train to overtake the longer train = 30 s

To Find:

◈ Speed of longer train

Solution:

Let

• The speed of longer train be x m/s
• The relative speed of the other trai would be = 30 - x m/s

Here the total distance travelled by short train will be,

➝ 120 + 240

➝ Distance by the short train = 360 m

It is given that time taken is 30 s,

We know that

⪼ Speed = Distance/Time

⪼ Time = Distance /Speed

• Time = 30 sec
• Distance = 360 - x

➳ 30 = 360/{30-x}

Cross multiply

➳ 30 (30 - x) = 360

➳ 30 - x = 360/30

➳ 30 - x = 12

➳ -x = 12 - 30

➳ x = 18 m/s

∴ The speed of the long train is 18 m/s

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☯ Know More

›› Speed is a scalar quantity, that is it has only magnitude and no direction

›› Speed = Distance/Time

›› SI unit of speed is m/s

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