Question

train crosses a tree in 20 seconds and a man cycling at 5 km/hr in the opposite direction in 18 seconds. What is the length of the train?

Answer 1

$\huge \underline \mathbb \red {ANSWER}$

Let the speed of the train be x kmph and length of train = L Km.

∴ L = 18x. Also, cycle is in opposite direction. ∴ Relative speed = x + 5

. So 18/(60x60) = L/x+5 →x+5 → 200L = 180L + 5 ∴ L=1/4km

Answer 2

Answer:

Length of the train= 250m

Step-by-step explanation:

Let  the speed of the train is x km/ hr and

the length of the train is L.

formula used:

speed*time=distance

L= 20x. ...............(1)

Also, cycle is in opposite direction.

∴ Relative speed = x + 5.

speed*time=distance

So L = 18(x + 5).........(2)

now equate both the equations(1) and (2),

we get,

18(x+5) =20x,

then x = 45

now put the value of x in equation  (1) and change into metre

Hence L =20 × 45 ×5/18 =250m

∴ Length of the train = 250m

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