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Q:

A bus covers its journey at the speed of 80km/hr in 10hours. If the same distance is to be covered in 4 hours, by how much the speed of bus will have to increase ?

A) 85 km/hr B) 95 km/hr
C) 105 km/hr D) 120 km/hr

Answer:   D) 120 km/hr



Explanation:

Initial speed = 80km/hr
Total distance = 80 x 10 = 800km
New speed = 800/4 =200km/hr
Increase in speed = 200 - 80 = 120km/hr

Q:

Buses start from a bus terminal with a speed of 20 km/hr at intervals of 10 minutes. What is the speed of a man coming from the opposite direction towards the bus terminal if he meets the buses at intervals of 8 minutes?

A) 5 kmph B) 6 kmph
C) 7.5 kmph D) 8 kmph
 
Answer & Explanation Answer: A) 5 kmph

Explanation:

Let p be the speed of man in kmph

According to the given data in the question,

Distance travelled by bus in 10 min with 20 kmph == Distance travelled by man in 8 min with (20 + p) kmph in opposite direction

=> 20 x 10/60 = 8/60 (20 + p)

=> 200 = 160 + 8p

=> p = 40/8 = 5 kmph.

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1 45
Q:

With an average speed of 40 km/hr, a train reaches its destination in time. If it goes with an average speed of 35 km/hr, it is late by 15 minutes. Find the length of the total journey?

A) 70 kms B) 60 kms
C) 45 kms D) 30 kms
 
Answer & Explanation Answer: A) 70 kms

Explanation:

Let the time taken by train be 't' hrs.

Then,

40t = 35t + 1560

40t = 35t + 35/4

t = 7/4 hrs

Therefore, Required length of the total journey d = s x t

= 40 x 7/4

= 70 kms.

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3 403
Q:

Ashwin fires two bullets from the same place at an interval of 15 minutes but Rahul sitting in a bus approaching the place hears the second sound 14 minutes 30 seconds after the first. If sound travels at the speed of 330 meter per second, what is the approximate speed of bus?

A) 330/29 m/s B) 330 x 30 m/s
C) 330/14 m/s D) 330/900 m/s
 
Answer & Explanation Answer: A) 330/29 m/s

Explanation:

Second gun shot take 30 sec to reach rahul imples distance between two.

given speed of sound = 330 m/s

Now, distance = 330 m/s x 30 sec 

 

Hence, speed of the bus = d/t = 330x30/(14x60 + 30) = 330/29 m/s.

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2 302
Q:

Important Time and Distance formulas with examples.

Answer

1. How to find Speed(s) if distance(d) & time(t) is given:


 


 Speed (S) = Distance (D)Time (T)  


 


Ex: Find speed if a person travels 4 kms in 2 hrs?


Speed = D/T = 4/2 = 2 kmph.


 


2.  Similarly, we can find distance (d)  if speed (s) & time (t) is given by


 


Distance (D) = Speed (S) x Time (T)


 


Ex : Find distance if a person with a speed of 2 kmph in 2 hrs?


Distance D = S X T = 2 x 2 = 4 kms. 


 


3.  Similarly, we can find time (t) if speed (s) &  distance (d) is given by


 


Time (T) = Distance (D)Speed (S)


 


Ex : Find in what time a person travels 4 kms with a speed of 2 kmph?


Time T = D/S = 4/2 = 2 hrs.


 


4. How to convert  km/hr into m/sec :


 


P km/hr = P x 518 m/sec


 


Ex : Convert 36 kmph into m/sec?


36 kmph = 36 x 5/18 = 10 m/sec 


 


5. How to convert  m/sec into km/hr :


 


P m/sec = P x 185 kmph.


 


Ex : Convert 10 m/sec into km/hr?


10 m/sec = 10 x 18/5 = 36 kmph.


 


6.  If the ratio of the speeds of A and B is a:b, then the ratio of the times taken by them to cover the same distance is b : a.


 


7.  Suppose a man covers a certain distance at x km/ hr and an equal distance at y km/hr . Then, the average speed during the whole journey is 2xyx+y km/hr.

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4 295
Q:

Two trains are running with speeds 30 kmph and 58 kmph respectively in the same direction. A man in the slower train passes the faster train in 18 seconds. Find the length of the faster train?

A) 105 mts B) 115 mts
C) 120 mts D) 140 mts
 
Answer & Explanation Answer: D) 140 mts

Explanation:

Speeds of two trains = 30 kmph and 58 kmph

=> Relative speed = 58 - 30 = 28 kmph = 28 x 5/18 m/s = 70/9 m/s

Given a man takes time to cross length of faster train = 18 sec

 

Now, required Length of faster train = speed x time = 70/9  x  18 = 140 mts.

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2 299
Q:

A train-A passes a stationary train B and a pole in 24 sec and 9 sec respectively. If the speed of train A is 48 kmph, what is the length of train B?

A) 200 mts B) 180 mts
C) 160 mts D) 145 mts
 
Answer & Explanation Answer: A) 200 mts

Explanation:

Length of train A = 48 x 9 x 5/18 = 120 mts

Length of train B = 48 x 24 x 5/18 - 120

=> 320 - 120 = 200 mts.

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2 427
Q:

Tilak rides on a cycle to a place at speed of 22 kmph and comes back at a speed of 20 kmph. If the time taken by him in the second case is 36 min. more than that of the first case, what is the total distance travelled by him (in km)?

A) 132 km B) 264 km
C) 134 km D) 236 km
 
Answer & Explanation Answer: B) 264 km

Explanation:

Let the distance travelled by Tilak in first case or second case = d kms

Now, from the given data,

d/20 = d/22 + 36 min

=> d/20 = d/22 + 3/5 hrs

=> d = 132 km.

 

Hence, the total distance travelled by him = d + d = 132 + 132 = 264 kms.

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0 382
Q:

A train covers 180 km distance in 5 hours. Another train covers the same distance in 1 hour less. What is the difference in the distances covered by these trains in one hour if they are moving in the same direction?

A) 15 kms B) 9 kms
C) 6 kms D) 18 kms
 
Answer & Explanation Answer: B) 9 kms

Explanation:

The first train covers 180 kms in 5 hrs

=> Speed = 180/5 = 36 kmph

Now the second train covers the same distance in 1 hour less than the first train => 4 hrs

=> Speed of the second train = 180/4 = 45 kmph

Now, required difference in distance in 1 hour = 45 - 36 = 9 kms.

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