1.
A and B are 25 km apart. If they travel towards each other, they meet after one hour. A travels faster than B. Find the speed of A, if he overtakes B after 5 hours, moving in the direction of B.
Correct Answer
C. 15 km/hr
Explanation
Let the speed of A and B be u km/hr and v km/hr respectively
When they travel in opposite directions u + v = 25 ------ > (i)
When they travel in same direction 5u – 5v = 25
u – v = 5 ----------- > (ii)
Solving equation (i) and (ii), we get
u = 15 km/hr.
2.
A man in a train notices that he can count 24 telephone posts in 3 minutes. If they are each 60m apart, then what is the speed of the train?
Correct Answer
A. 27.6 kmpH
Explanation
24 telephone posts each 60m apart implies the distance between frist post to the last post is (24 – 1) X 60
= 23 X 60 = 1380m
∴ Distance = 1380 m
∴ Speed of the train = 1380/3 X 60 = 138/18 m/s
= (138/18 X 18/5) = 27.6 kmph.
3.
A train can travel 50% faster than a car. Both start from point A at the same time and reach point B, which is 330 km away fro A, at the same time. On the way, however, the train lost about 88 minutes while stopping at the station. The speed of the train is
Correct Answer
B. 112.5 kmpH
Explanation
Let the speed of the car be z kmph
Then the speed of the train = x X 150/100 = 3x/2
Now, 330/x – 330/ 3x/2 = 88/60
330/x – 220/x = 88/60
330 – 220/x = 88/60
110/x = 88/60
∴ x = 60 X 110/88 = 75
∴ The speed of the car = 75 kmph
∴ Speed of the train = 3x/2 = 75 X 3/2 = 112.5 kmph.
4.
Two trains A and B, start from stations X and Y towards each other. They take 4 hours 48 minutes and 3 hours 20 minutes to reach Y and X respectively after they meet. If train A is moving at 45 km/hr, then the speed of train B is
Correct Answer
D. 54 kmpH
Explanation
Let the speed of train A be SA = 45 kmph and that of train B be SB
Then, time taken by train A = TA
= 4 hours 48 minutes = 4 + 48/60 = 24/5
Time taken by train B = TB
= 3 hours 20 minutes = 3 1/3 hours = 10/3 hours
Using formula SA/SB = √TB/TA
∴ 45/SB = √ 10/3 X √5/24 = √25/36 = 5/6
SB = 45 X 6/5 = 54 kmph.
5.
The distance between two places A and B is 320 km. A car departs from place A for place B at a speed of 55 kmph at 7 am. Another car departs from place B for place A at a speed of 45 kmph at 11 am. At what time will both cars meet each other?
Correct Answer
B. 12:00 PM
Explanation
Distance travelled by the first car in 4 hours = Speed X Time = 55 X 4 = 220 km
Remaining distance = 320 – 220 = 100 km
Time for both cars to meet = Distance/Relative speed
= 100/55 + 45 = 100/100 = 1 hour
∴ Both the cars will meet after 1 hour means at (11 am + 1) = 12 pm.
6.
A train running at the speed of 35 metres per second crosses a bridge in 20 seconds. Another train which is 140 metres shorter than the previous train crosses the same bridge at the speed of 40 metres per second. Find the time taken by the second train to cross the bridge.
Correct Answer
A. 14 seconds
Explanation
Let the length of the bridge be x m and that of first train be y m.
∴ x + y/35 = 20
∴ x + y = 700
Again, x + (y – 140)/40 = t
x + y – 140/40 = t
700 – 140/40 = t
∴ t = 560/40 = 14 seconds.
7.
A train running at a speed of 194.4 kmph passes a man walking in opposite direction at the speed of 6 m/sec in 15 seconds. What is the length of the train?
Correct Answer
C. 900 m
Explanation
Relative speed = 194.4 X 5/18 +6
= 60 m/sec
∴ Time = 15 seconds
∴ Length of the train = 60 X 15 = 900 metres.
8.
A man takes a total of 6 hours 30 minutes by walking to a certain place and coming back by cycle. He would have gained 1 hour 30 minutes by cycling both ways. The time he would take to walk both ways is
Correct Answer
A. 8 hours
Explanation
By cycling + by walking = 6 hours 30 minutes
One way by cycling = 6 hrs 30 min – 1 hr 30 min/2
= 2 hours 30 minutes
∴ By walking both ways = 2 (6 hrs 30 min – 2 hrs 30 min) = 8 hours.
9.
A person travelled a distance of 30 km in 8 hours. He travelled partly on foot at the rate of 3 kmph and partly on bicycle at the rate of 5 kmph. The distance travelled on foot is
Correct Answer
B. 15 km
Explanation
Let the distance travelled on foot be x km
Then, x/3 + (30 – x)/5 = 8
5x + 3 (30 – x) = 120
∴ x = 15 km.
10.
A train running at 75 kmph crosses a platform in 1 minute. What is the length of the platform (in metres)?
Correct Answer
D. Data Inadequate
Explanation
Length of the train is not given
We know that
Time = Length of train + Length of platform/Speed
1 = Length of train + Length of platform/ 75 X 5/18
Hence we can’t determine the length of the platform.
11.
A train travelling at a speed of 60 km/hr crosses a platform in 20 seconds. What is the length of the train?
Correct Answer
D. Data Inadequate
Explanation
Speed = Distance/Time
60 = L + P/20
∴ L + P = 60 X 20
Hence we can’t determine the length of the platform.
12.
Car M takes 5 hours to travel from Point A to B. It would have taken 6 hours, if the same car had travelled the same distance at a speed which was 15 kmph less than its original speed. What is the distance between Points A and B?
Correct Answer
B. 450 km
Explanation
Let the distance be D km
Then, D/5 = D/6 + 15
D/5 – D/6 = 15
6D – 5D/30 = 15
∴ D = 15 X 30 = 450 km.
13.
Ram started his journey at 8 am at 8 km/hr. Hamid started from the same spot in the same direction at 8:30 am at 10 km/hr. Hamid overtakes Ram at
Correct Answer
D. 10.30 am
Explanation
Relative speed = 10 – 8 = 2 kmph
Ram covers the distance between 8 am to 8:30 am = 8/2 = 4 km
∴ Reqd time = 4/2 = 2 hours
Hence Hamid overtakes Ram at (8:30 am + 2 hrs) = 10:30 am.
14.
A train travelling at 57 km/hr passes another train half of its length travelling in the opposite direction at 33 km/hr in 18 seconds. If it passes a railway platform in 1.2 minutes, what is the length of the platform?
Correct Answer
B. 840 metres
Explanation
Distance travelled with relative speed 57 + 33 = 90 km/hr in 18 seconds
90 (5/18) X 18 = 450 m
Ratio of lengths = First : Second
2 : 1
∴ Length of first train = 300 m
Now, distance travelled by 1st train at 57 km/hr in 72 seconds
= 57 (5/18) X 72 = 1140 m
∴ Length of platform = 1140 – 300 = 840 m.
15.
A car covers a distance between A and B in 45 minutes. If the speed of the car is reduced by 8 km per hour then the same distance is covered by 49.5 minutes. What is the distance between A and B?
Correct Answer
D. 66 km
Explanation
Let the distance between A and B be d km
Then, d/ 45/60 – d/ 49.5/60 = 8
4d/4 – 120d/99 = 8
132d – 120d/99 = 8
∴ d = 8 X 99/12 = 66 km.
16.
A train is scheduled to cover the distance between two stations 90 km apart in one hour. If it travels 55 km at a speed of 80 kmph, find the speed for the remaining journey to complete it within the scheduled time.
Correct Answer
A. 112 kmpH
Explanation
Distance between two stations = 90 km
Let the speed for the remaining journey be x kmph
∴ 55/80 + 35/x = 1
35/x = 1 – 55/80 = 25/80
∴ x = 35 X 80/25
∴ x = 112 kmph
∴ Train has to move at the speed of 112 kmph.
17.
Mohit travels 972 km in 10.5 hours in two stages. In the first part of the journey, he travels by bus at the speed of 78 km/hr. In the second part of the journey, he travels by train at the speed of 112 km/hr. How much distance does the travel by train?
Correct Answer
A. 504 km
Explanation
We use only allegation on speed (km/hr) to get ration of time spent in bus and train.
Overall speed = 972/10.5 = 1944/21 = 648/7
Using allegation method
Bus Train
78 112
92 4/7
19 3/7 : 14 4/7
136/7 : 102/7
136 : 102
4 : 3
Time spent in train = 10.5 (3/7) = 4.5 hours = 504 km.
18.
Sitting in a train, Kapil notices that he can count 21 telephone posts in one minute. If they are known to be 80 metres part, then at what speed is the train travelling?
Correct Answer
A. 96 km/hr
Explanation
No. of telephone posts = 21
No. of gaps between 21 posts are 20 and two posts are 80 metres apart.
It means 20 X 80 metres covered in 1 minute.
∴ Distance = 20 X 80 = 20 X 80/1000 km
= 1.6 km
∴ Speed of train = 1.6 X 60/1 = 96 km/hr.
19.
A train running at an average speed of 54 kmph crosses a pole in 14 seconds. How much time will a man take to cross the same train if it is stationary, when he is cycling at a speed of 7 kmph? (in seconds)
Correct Answer
D. 108
Explanation
Length of train = 54 X 14 X 5/18 = 210 metres
∴ Time taken by the man to cross the stationary train = 210 X 18/ 7 X 5 = 6 X 18
= 108 seconds.
20.
The average speed of a car, a bus and a train together is 68 kmph. The ratio of their speeds is 3 : 5 : 9. What is the average speed of the train and the bus together?
Correct Answer
A. 84 kmpH
Explanation
The ratio of the speed of the car, the bus and the train = 3x : 5x : 9x
∴ 3x + 5x + 9x = 68 X 3
17x = 68 X 3
x = 68 X 3/17 = 12 km
∴ Average speed of the train and bus = 5x + 9x/2
= 60 + 108/2
= 168/2 = 84 kmph.
21.
A car covers the first 40 km in 35 minutes and the remaining 105 km in 85 minutes. What is the average speed of the car?
Correct Answer
B. 72.5 kmpH
Explanation
Avg Speed = Total distance travelled/Time taken to travel the distance
40 + 105/ (35 + 85)/60 = 145/120 X 60 = 72.5 kmph
22.
Gaurav drove at the speed of 65 kmph from his home to a resort. While returning he got stuck in traffic and took 3 more hours; he could drives only at the speed of 50 kmph. How many kilometres did he drive each way?
Correct Answer
C. 650
Explanation
Let the distance be x km
Then, x/50 – x/65 = 3
13x – 10x/650 = 3
∴ x = 3 X 650/3 = 650 km
23.
A 218 metre long train travelling at 63 kmph can cross a platform in 32 seconds. If a man can cross the same platform in 3 minutes, what is the speed of the man (in m/sec)?
Correct Answer
B. 1.9
Explanation
Speed of train = Length of platform + Length of train/Time
Length of platform = 63 X 32 X 5/18 – 218
= 560 – 218 = 342 m
∴ Speed of man = 342/ 3 X 60 = 342/180 = 1.9 m/s
24.
A 600-metre-long train crosses a platform is 78 seconds while it crosses a pole in 36 seconds. What is the length of the platform?
Correct Answer
B. 700 m
Explanation
Speed of train = 600/36 = 50/3 m/sec
Let the length of the platform be x metres
Then, x + 600/78 = 50/3
3x + 1800 = 3900
3x = 2100
∴ x = 700 m.
25.
Excluding stoppages, the speed of a bus is 81 km/hr and including stoppages, it is 54 km/hr. For how many minutes does the bus stop per hour?
Correct Answer
A. 20 min
Explanation
Due to stoppages, bus covers 81 – 54 = 27 km less
∴ Time taken to cover 27 km = 27/81 X 60 = 20 min
Hence the bus stops 20 minutes per hour.