aptitude : : time and distance
 
@ : Home  >  Aptitude  >  time and distance  >   Questions & Answers
 
Overview
Important Formulas
  Exercise
   Exercise 2
   Exercise 1
1.
Two trains of equal length are running on parallel lines in the same direction at 45 km/h and 35 km/h. The faster train passes the slower train in 27 s. The length of each train is:
 
A.
250 m

B.

300 m
C.
350 m
D.
400 m
   
  Answer Discuss in Forum Calculator Workspace
Answer: B
Explanation :
Let the length of each train be X m.
Relative speed= (45 + 35) km/h = (80X 5/18) m/s
  = 40X5/9 = 2x/27= 300 m
              X=300 m
So, the length of each train is 300 m. 






 
2.
A train 100 m long completely passes a man walking in the same direction at 2 km/h in 9 s and a car travelling in opposite direction in 3 s. At what speed was the car travelling?
 
A.
78 km/h

B.

75 km/h
C.
74 km/h
D.
72 km/h
   
  Answer Discuss in Forum Calculator Workspace
Answer: A
Explanation :

Speed of the man = (2x 5/8) m/s = 5/9 m/s

Let the speed of the train be x m/s

    x- 5/9 = 100/9

    x= 100/9 + 5/9+ 105/9 =35/9 m/s

Let the speed of the car be y m/s .

    35/3 + y = 100/3

  y= 100/3 -35/3 =65/3 m/s

So, speed of the car =( 65/ 3 X 18/5) km/h =78 km/h            







 
3.
A train speeds past a pole is 10 s and speeds past a platfrom of 300 m in 25 s. Its length in metres is:
 
A.
150 m

B.

200 m
C.
180 m
D.
250
   
  Answer Discuss in Forum Calculator Workspace
Answer: B
Explanation :

Let the length of the train =x m and speed of the train = y m/s Then,

                         y= x/10 and y= x+300/25

On solving Eqs. (i) and (ii), we got

                         x/10 =x+300/25

      = 25x= 10x +3000

      = 15x = 3000 = x =200

   x= 200

So, the length of the train is 200 m. 

 







 
4.
A 260 m long train crosses a platform thrice its length in 80 s. what is the speed of the train in km/h?
 
A.
52.4

B.

46.8
C.
36.1
D.
cannot be determind
   
  Answer Discuss in Forum Calculator Workspace
Answer: B
Explanation :
Speed = 260+ (3X260)/80 m/s
  = 1040/80= 13 m/s  
  = 13X18/5 = 46. 8 km/h 






 
5.
A train 130 m long passes a bridge in 20 s moving with a speed of 90 km/h. Find the length of the bridge:
 
A.
364 m

B.

369 m
C.
370 m
D.
372 m
   
  Answer Discuss in Forum Calculator Workspace
Answer: C
Explanation :

Speed of the train

     = Length of the (train + stationary object) / Time taken to cross the stationary object

Let the length of the bridge be x.

Speed of the train = 90 km/h = 90X(5/18) m/s = 25 m/s 

25 = 130+x/20

   x= (25X 20 - 130) m

     = 370 m 







 
6.
A train moving with a speed of 25 m/s crosses a standing man in 16 s. what is the length of the train?
 
A.
160 m

B.

250 m
C.
320 m
D.
400 m
   
  Answer Discuss in Forum Calculator Workspace
Answer: D
Explanation :
25= length of the train/16
Length  of the train = (25X16)m = 400 m 






 
7.
A good train left A for B at 3 pm at an average speed of 60 km/h. At 6 pm, an express train also had left A for B a parallel track at an average speed of 90 km/h. how far from A, is the express train expected to overtake the goods train?
 
A.
360 km

B.

630 km
C.
450 km
D.
540 km
   
  Answer Discuss in Forum Calculator Workspace
Answer: D
Explanation :

Distance covered by the goods train in 

              3 h = (60X3) km = 180 km

Relative speed =(90-60) km/h =30 km/h

Let X be the time taken for the express train to overtake the goods train.

Then,   30= 180/x

              X = (180/30) h = 6 h

Distance from A =(90X60) km =540 km  







 
8.
The respective ratio between the speeds of a car, a jeep and a tractor is 3:5:2. The speed of the jeep is 250% the speed of the tractor which covers 360 km in 12 h. what is the average speed of car and jeep together?
 
A.
60 km/h

B.

75 km/h
C.
40 km/h
D.
cannot be determined
   
  Answer Discuss in Forum Calculator Workspace
Answer: A
Explanation :
Speed of tractor = 360/12 km/h
Speed of jeep = 30 X 250% = 75 km/h
Speed of car = 3/5 X 75 = 45 km/h
Average speed of car and jeep together = 75+45/2 = 60 km/h






 
9.
A walks at 3 km/h and 4 h after his start, B cycles after him at 5 km/h. How far from the start does B catch up with A?
 
A.
30 km

B.

34 km
C.
36 km
D.
38 km
   
  Answer Discuss in Forum Calculator Workspace
Answer: A
Explanation :
Distance covered by A when B starts
                       = (3X4) km = 12 km
Relative speed =(5-3) km/h = 2 km/h
Then, the time of travel for B = (12/2) h= 6h
Distance travelled by B = (5x6) km = 30 km        






 
10.
Two men starting from the sample place walk at the rate of 5 km/h and 5.6 km/h, respectively. what time will they take to be 3 km apart, if they walk in the same directions?
 
A.
3 h

B.

4 h
C.
5 h
D.
6 h
   
  Answer Discuss in Forum Calculator Workspace
Answer: C
Explanation :
Let the required time = X h
Relative speed =(5.6-5) km/h =0.6 km/h 
   0.6= 3/x = X = (3/0.6) 
   H = 5 h   






 

Pages 1  2    3    4    5    6    7    8