Problems on trains

1) A train 270 m long is moving at a speed of 24kmph. It will cross a man coming form the Opposite direction at a speed of 3kmph, in 

A.    12 s

B.    24 s

C.    36 s

D.    45 s

2) Two trains each 200 m long are running on parallel rails at the rate of 40kmph and 45kmph respectively. In how much time will they cross each other, if they are running in the same direction? 

A.    128 s

B.    288 s

C.    342 s

D.    368 s

3) A train 110 m long is traveling at a speed of 59kmph. The time in which it will pass a passer by, walking at 4kmph in the same directions, is 

 A.    7 1/5 s

 B.    3 2/3 s

C.    4 3/5 s

 D.    5 1/3 s

4) A train takes 18 seconds to pass completely though a station162 m long and 15 seconds though another station 120 m long. The length of the train is 

A.    60m

 B.    70m

C.    80m

D.    90m

5) A train 150 m long takes 20 seconds to cross a platform 450 m long. The speed of the train is 

A.    20 m/s

B.    25 m/s

C.    30 m/s

 D.    40 m/s

Time and distance

1) A man walks at 5kmph for 6hr and at 4km/h for 12hr. His average speed is 

A.    4 1/3 km/h

B.    7 2/3 km/h

C.    9 ½ km/h

D.    8 km/h

Answer : A.

Avg speed = total distance/total time
= 5*6 + 4*12 / 18
=4 1/3 km/h

2) A man can cover a distance in 1hr 24min by covering 2/3 of the distance at 4 km/h and the rest at 5km/h. The total distance is 

A.    5km

 B.    6km

C.    7km

D.    8km

Answer : B.

Distance = 2/3S
distance=1-2/3S=1/3S
21/15 hr=2/3 S/4 + 1/3s /5
84=14/3S * 3
S= 6km

3) The ratio between the speeds of two trains is 7: 8. If the second train runs 440 kms in 4 hours, then the speed of the first train is: 

A.    47.4 km/hr

 B.    57.19 km/hr

C.    68.13 km/hr

 D.    96.25 km/hr

Answer : D.

Let the speed of two trains be 7x and 8x km/hr.
Then, 8x = (440/4) = 110
x = (110/8) = 13.75
Hence, speed of first train = (7 x 13.75) km/hr = 96.25 km/hr.

4) A train 140m long is running at 60kmph. In how much time will it pass a platform 260m long? 

 A.    15 seconds

B.    24 seconds

 C.    28 seconds

 D.    30 seconds

Answer : C.

Distance travelled = 140 + 260m = 400m
Speed = 60 * 5/8 = 50/3m
Time = 400 * 3/50 = 24 Seconds

5) In covering a distance of 30 km, A takes 2 hours more than B. If A doubles his speed, then he would take 1 hour less than B. A's speed is: 

A.    5 km/h

 B.    8 km/h

C.    10 km/h

D.    15 km/h

Answer : A.

Let A's speed be X km/hr.
Then, 30/x - 30/2x = 3
6x = 30
x = 5 km/hr.

Number series

1)2, 7, 14, 23, ?, 47 

A.    31

B.    28

C.    34

D.    38

Answer : C.

The given sequence is +5, +7, +9, —— 
ie. 2+ 5 = 7, 7 + 7 = 14, 14 + 9 = 23
Missing Number = 23 + 11 = 34.

2) 4, 6, 12, 14, 28, 30, ? 

 A.    32

 B.    64

 C.    62

 D.    60

Answer : D.

The given sequence is a combination of two series 4, 12, 28, .... and 6, 14, 30, .... The pattern is +8, +16, +32. So, the missing number = (28 + 32) = 60

3) 4, 9, 13, 22, 35, ? 

A.    57

 B.    70

 C.    63

 D.    75

Answer : A

Sum of two consecutive numbers of the series gives the next number.

4) 11, 13, 17, 19, 23, 29, 31, 37, 41, ? 

A.    43

B.    47

C.    51

 D.    53

Answer : A.

The series consists of prime numbers.

5) 15, 31, 63, 127, 255, ? 

 A.    513

 B.    511

C.    523

 D.    517

Answer : B.

Each number is double of the preceding one plus 1.