A.36 km/hr

B.48 km/hr

C.72 km/hr

D.96 km/hr

E.102 km/hr

2) The ratio of the length of two trains A and B is 5 : 8 and the ratio of the time taken by both trains to cross a man standing on a platform is 2 : 1. If the speed of train A is 40 km/h, find the speed of train B.

A.145km/hr

B.121km/hr

C.117km/hr

D.128km/hr

E.None of these

3) Train A running at the speed of 60 kmph crosses a bridge of the same length as that of the train in 42 seconds. If train B crosses the same bridge in 40 seconds and the speed of train B is 12 kmph more than that of A, then find the length of train B.

A.400 m

B.300 m

C.350 m

D.450 m

E.500 m

4) Train A crosses another train of the same length moving in the opposite direction in 20 seconds. If train A crosses a standing man in 18 seconds with the speed of 72 kmph, then find the speed of train B?

A.24 m/sec

B.18 m/sec

C.16 m/sec

D.12 m/sec

E.None of these

5) Train A crosses a 150 m long tunnel in 20 seconds and train B crosses a man running in the opposite direction at the speed of 30 kmph in 8 seconds. If the length of train A is 75% more than the length of train B, then find the speed of train A.

A.60

B.90

C.80

D.72

E.Cannot be determined

Answers :

1) Answer: C

Speed of train = 36 km/hr = 36 × 5/18 = 10 m/sec

Length = speed × time = 45 × 10 = 450 meter

Let the speed of another train be x m/sec.

Relative speed = 10 + x

Length = 450 + 450 = 900 m

⇒ (10 + x) = 900/30

⇒ x = 20 m/sec

Speed of the other train = 20 × 18/5 = 72 km/hr

2) Answer: D

Let the length of A and B be 5x and 8x respectively and the time taken by the two trains A and B to cross the man be 2t and t respectively.

So the speed of first train = 5x/2t

Now 5x/2t = 40

Or, x/t = 16

Now the speed of train Y is 8x/t= 8*16 = 128km/h

3) Answer: D

Length of train A = x

Length of bridge = x

2x = 60 * 5/18 * 42

x = 350 m

350 + Length of train B = 72 * 5/18 * 40

Length of train B = 450 m

4) Answer: C

Speed of the train A=72*5/18=20 m/sec

Length of the train A=20*18=360 m

Length of the train B=360 m

(20+x)=(360+360)/20

(20+x)=36

x=16 m/sec

5) Answer: E

Length of train B = 4x

Length of train A = 4x * 175/100 = 7x

Speed of train A = y

Speed of train B = z

7x + 150 = y * 5/18 * 20

4x = (z + 30) * 5/18 * 8

We cannot find the answer.