Aptitude

1

A train 120 meters long is running with a speed of 60 km/hr. In what time will it pass a boy who is running at 6 km/hr in the direction opposite to that in which the train is going?

a

6.54 sec

b

44.32 sec

c

55 sec

d

30.2 sec

Speed of train relative to boy= (60 + 6) km/hr = 66 km/hr

= [66 xx 5/18] m/sec = [55/3] m/sec.

Time taken to pass the boy= [120 xx 3/55] sec = 6.54 seconds

2

Find the speed of the train, if a train 142 m long passes a pole in 6 seconds.

a

77.2 km/hr

b

79.6 km/hr

c

84.9 km/hr

d

79.2 km/hr

Speed = [142/6] m/sec

= [23.6 ** 18/5] km/hr

= 84.9 km/hr

3

The driver of a maruti car driving at a speed of 68km/h locates a bus 40m ahead of him. After 10sec the bus is 60m behind. The speed of the bus is

a

30km/hr

b

32km/hr

c

25km/hr

d

38km/hr

Let the speed of the bus be x m/s
speed of the car = 68km/hr (or) 170/9 m/s
in 10s the car covers a distance of 100m (40m + 60m = 100m) at a speed of (170/9 – x)m/s
distance = speed*time
100 = (170/9 -x) **10
x = 80/9 m/s
Now convert it to km/hr which is 32 km/hr

4

A train 150 m long is running with a speed of 68 kmph. In what time will it pass a man who is running at 8 kmph in the same direction in which the train is going?

a

6s

b

9s

c

10s

d

12s

Speed of the train relative to man = (68 - 8) kmph = (60* 5/18) m/sec = (50/3)m/sec
Time taken by the train to cross the man I = Time taken by It to cover 150 m at 50/3 m / sec
= 150 *3/ 50 sec = 9 sec