Question

1. A train with 90 km/h crosses a bridge in 36 seconds. Another train 100 metres shorter crosses the same bridge at 45 km/h. What is the time taken by the second train to cross the bridge ?

61 seconds
63 seconds
62 seconds
64 seconds

Answer 1

Answer:

64 seconds

Explanation:

Speed of the first train = 90 km/h

= 90 × 5/18 = 25 m/s

Let the length of bridge and train be

25 × 36 = 900 m

Speed of the second train = 45 km/h

= 45 × 5/18 = 25/2

Now, we know Distance / time = speed.

time = distance / speed

Now, we know the second train is 100 m shorter so ,

= (900 - 100) x 2/25

= 800 x 2/25 = 64 sec.

Mark it as brainliest if u find it helpful.

Answer 2

Answer:

Option D.

Explanation:

Train A, Speed = 90kmph

=90*(5/18)m/s = 25m/s = 25m/s, t=36s

Let length, L = x+y = time*speed = 25*36 = 900m

=800m, Speed= 45*(5/18) = (25/2) m/s

t= (Distance/Speed) = (800/(25/2)) = (1600/25) = 64 seconds