# Problems on Trains Quiz Set 014

### Question 1

Two trains are moving in opposite directions on two parallel tracks. How many seconds will they take to cross each other if the sum of their lengths is 328m, and the sum of their speeds is 82m/s.?

A

4 sec.

B

5 sec.

C

3 sec.

D

6 sec.

Soln.
Ans: a

The total distance is equal to the sum of the lengths of the trains, so s = 328. This distance has to be covered at a net relative speed equal to the sums of the speeds of the two trains, so v = 82. The time will be distance/speed = \$328/82\$ = 4 sec.

### Question 2

A train running at 8km/h leaves a railway station 18 hours later than another train, and meets it in 6 hours. What is the speed of the other train?

A

2 km/h.

B

3 km/h.

C

5 km/h.

D

4 km/h.

Soln.
Ans: a

Let the speed of the train be v km/h. Distance travelled by this train in (6 + 18) hours = 24v km. Equating this to the distance travelled by the second train we get 24v = 8 × 6, which gives v = 2 km/h.

### Question 3

Two trains are moving in same direction on two parallel tracks. How many seconds will they take to cross each other if the sum of their lengths is 332m, and the difference of their speeds is 83m/s?

A

4 sec.

B

5 sec.

C

3 sec.

D

6 sec.

Soln.
Ans: a

The total distance is equal to the sum of the lengths of the trains, so s = 332. This distance has to be covered at a net relative speed equal to the difference of the speeds of the two trains, so v = 83. The time will be distance/speed = \$332/83\$ = 4s.

### Question 4

A train passes two persons walking in the same direction as the train. The time it takes to move past the man running at 4km/h is 6sec, whereas the time it takes to cross the other man running at 11km/h is 7sec. What is the speed of the train?

A

53 km/h.

B

54 km/h.

C

52 km/h.

D

55 km/h.

Soln.
Ans: a

Let the speed of the train be v km/h. Length of the train calculated with the data for the first man = \$(v - 4) × 6\$. It should equal the length obtained from the data for the second man. So \$(v - 4) × 6\$ = \$(v - 11) × 7\$. Please note that we have not converted seconds to hours because that factor will ultimately cancel away. Solving for v we get 53km/h.

### Question 5

A train 936 meters long is moving at a speed of 72m/s. How long will it take to cross a man who is running in the opposite direction at a speed of 84m/s?

A

6 sec.

B

7 sec.

C

5 sec.

D

8 sec.

Soln.
Ans: a

The distance to be covered is equal to the length of the train, so s = 936. This distance has to be covered at a net relative speed equal to the sums of the speeds of the man and the train, so v = 72 + 84 = 156. The time will be distance/speed = \$936/156\$ = 6 s. This Blog Post/Article "Problems on Trains Quiz Set 014" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-05-13