 # Time & Distance (10)

1. A person travels from A to B at a speed of 40 km/hr and returns by increasing his speed by 50%. What is his average speed for both the trips?
1. 60 km/hr
2. 56 km/hr
3. 52 km/hr
4. 48 km/hr

Explanation :-

Speed from A to B = 40 km/hr
Speed from B to A = 150% of 40 = 60 km/hr
Average speed = 2xy / (x + y) = (2*40*60) / (40*60) = 4800/100 = 48 km/h

2. A man in a train notices that he can count 21 telephone posts in one minute. If they are known to be 50 metres apart, at what speed is the train travelling?
1. 61 km/hr
2. 56 km/hr
3. 63 km/hr
4. 60 km/hr

Explanation :-

Number of gaps between 21 poles = 20
Therefore ,
Total distance between 21 poles = 20*50 = 1000 m = 1 km
Time taken = 1min = 1/60 hr
Speed = distance/time;
Speed = 1/(1/60) =1*60 = 60km/h

3. A truck covers a distance of 550 metres in 1 minute whereas a train covers a distance of 33 kms in 45 minutes. What is the ratio of their speed?
1. 2 : 1
2. 1 : 2
3. 4 : 3
4. 3 : 4

Explanation :-

Speed of track = 550  m/per minute.
Speed of bus = 33 kms /45 = 33000/45 m/minute
Ratio of their speeds = 550 : 33000/45
=> 55*45 3300 = 3 : 4

4. A person has to cover a distance of 6 km in 45 minutes. If he covers one-half of the distance in two-thirds of the total time; to cover the remaining distance in the remaining time, what should be his speed in km/hr?
1. 14 km/hr
2. 12 km/hr
3. 10 km/hr
4. 8 km/hr

Explanation :-

Remaing distance = 3 km
Remaining time = (1/3 * 45)min = 15 min = 1/4 hour.
Speed = Distance / Time
Speed = (3 / (1/4)) = 12 km/hr.

5. A man takes 5 hours 45 min in walking to a certain place and riding back. He would have gained 2 hours by riding both ways. The time he would take to walk both ways is
1. 11 hrs
2. 8 hrs 45 min
3. 7 hrs 45 min
4. 9 hts 20 min