# Time and Distance practice

1.

A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:

A. 130

B . 360

C . 500

D. 540

Answer: Option C

Explanation:

Speed = 78 x5/18 m/sec. = 65/3 m/sec.

Time = 1 minute = 60 seconds.

Let the length of the tunnel be x metres.

Then, (800 + x)/60 = 65/3

=> 3(800 + x) = 3900

=> x = 500.

2.

A person covers a certain distance at 7kmph .How many meters does he cover in 2 minutes.

A. 1900 m

B. 2400 m

C. 3200 m

D. None of these

Answer: Option B

Explanation:

speed=72kmph=72*5/18 = 20m/s

distance covered in 2min =20*2*60 = 2400m

3.

Bharani and Anand are 180 km apart. They started simultaneously towards each other at speeds of 10 kmph and 20 kmph respectively. In how many hours will they meet ?

A. 5

B. 4

C. 6

D. 7

Answer: Option C

Explanation:

Time taken to meet = Distance/relative speed = 180/(10+20) = 6 hours

4.

Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:

A. 1:2

B. 3:4

C. 3:2

D. none of these

Answer: Option C

Explanation:

Let the speeds of the two trains be x m/sec and y m/sec respectively.

Then, length of the first train = 27x metres, and length of the second train = 17y metres.

(27x+17y)/x+y = 23

27x + 17y = 23x + 23y 4x = 6y

x/y = 3/2

5.

A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?

A. 3.6 sec

B. 18 sec

C. 36 sec

D. 72 sec

Answer: Option C

Explanation:

Speed of train relative to jogger = (45 – 9) km/hr = 36 km/hr.

= (36 x 5/18)m/sec

= 10m/sec.

Distance to be covered = (240 + 120) m = 360 m.

Time taken = (360/10)sec = 36sec.

6.

Deepak walked at 4 kmph for a certain part of his journey and took an auto, travelling at 25 kmph for the rest of the journey. If he took 42 minutes for the entire journey, what part of the journey did he walk given that his average speed for the entire journey was 10 kmph?

A. 1 km

B. 2 km

C. 4 km

D. 5 km

Answer: Option B

Explanation:

Speed is 10 kmph; Time is 42 min

So, total distance = 42/60*10= 7 km

Let x km be the walking distance

Therefore, x/4 + (7-x)/25 = 42 min.= 7/10 hours

21x= 70-28=42

x= 2 km.

7.

Wind blows 160 miles in 330min.for 80 miles how much time required

A. 165

B. 162

C. 159

D. 160

Answer: Option A

Explanation:

160 miles= 330 min

1 mile = 330/160

80 miles=(330*80)/160=165 min.

8.

From height of 8 mts a ball fell down and each time it bounces half the distance back. What will be the distance travelled?

A. 30

B. 25

C. 18

D. 24

Answer: Option D

Explanation:

8+4+4+2+2+1+1+0.5+0.5+ and etc .. =24

9.

A car travels the first one -third of a certain distance with a speed of 10km/hr, the next one -third distance with a speed of 20km/hr, the last one-third distance with a speed of 60km/hr. The average speed of the car for the whole journey is:

A.18km/hr

B. 24km/hr

C. 30km/hr

D. 36km/hr

Answer: Option A

Explanation:

Let the whole distance traveled be x km and the average speed of the car for the whole journey be y km/hr.

Then, (x/3)/10 + (x/3)/20 + (x/3)/60 = x/y , x/30 +x/60 +x/180 = x/y,

10x/180 = x/y, y = 18km/hr

10.

Two trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is

A. 2 : 3

B. 4 : 3

C. 6 : 7

D. 9 : 16

Answer: Option B

Explanation:

Let us name the trains as A and B.

Then, (A’s speed) : (B’s speed) = b : a

= 16 : 9

= 4 : 3.