Speed Time And Distance - Aptitude MCQ Questions and Solutions with Explanations

1. Two trains started at the same time, one from A to B and other from B to A. if they arrived at B and A respectively in 4 hours and 9 hours after they passed each other, the ratio of the speeds of the two trains was:
A. 2:1

B. 3:2

C. 4:3

D. 5:4

Answer: Option B

A →____________________← B
Ratio of the speed of trains is given by;
(Speed of train A/ Speed train of B) = √b/√a.
= √9/√4.
= 3/2
= 3:2.

2. If a 250 m long train crosses a platform of same length as that of the train in 25 seconds, then the speed of the train is:
A. 150 m/sec

B. 200 m/sec

C. 20 km/h

D. 72 km/h

Answer: Option D

Speed of train = length of the train + length of platform /time
= (250+250)/25 = 20 m/sec = 72 km/h.

3. Two runner start running together for a certain distance, one at 5 km/h and another at 3 km/h. The former arrives one and half an hour before the latter. The distance in Km is :

A. 12

B. 20

C. 25

D. 36

Answer: Option B

Let X be the distance, then
(X/5)-(X/3) = (3/2)
X = 20 km.

4. A train 350 m long is running at the speed of 36 km/h. If it crosses a tunnel in 1 minute, the length of the tunnel in metres:
A. 200

B. 250

C. 300

D. 150

Answer: Option B

Let the length of the tunnel be x m.
Time = (Length of train + Length of tunnel) / Speed
60 = (350 +x)/10
[Speed = 36*5/18 = 10 m/sec]
x = 250 meters.
Therefore length of tunnel is 250 meters.

5. An athlete runs 200 meters race in 24 seconds. His speed in km/h is
A. 20

B. 24

C. 28.5

D. 30

Answer: Option D

Speed of athlete,
= 200m/24secs
= 200*18/5*24
= 30 km/hour.

6. A motor boat takes 2 hours to travel a distance of 9 km downstream and it takes 6 hours to travel the same distance against the current. The speed of the boat in still water and that of the current (in km/h) respectively are:
A. 6, 5

B. 3, 1.5

C. 8, 5

D. 9, 3

Answer: Option B

Downstream speed,
= 9/2 = 4.5 kmph
Upstream speed,
= 9/6 = 1.5 kmph
Thus, speed of boat in still water,
= (4.5 +1.5)/2 = 3 kmph.
Speed of current = (4.5-1.5)/2 = 1.5 km/h.