Time & Distance (17)

1. Busses start from a bus terminal with a speed of 20 km/hr at intervals of 10 minutes. What is the speed of a man coming from the opposite direction towards the bus terminal if he meets the buses at intervals of 8 minutes?
1. 3 km/hr
2. 4 km/hr
3. 5 km/hr
4. 7 km/hr
5. None of these

Answer & Explanation

Answer:- 3

Explanation :-

Distance between the buses  =  20*(60/10) km
Let the speed of the man be x km/h
For the man, 103km is covered in 8 minutes with a relative speed of  km/hr
speed of the man = 5 kmph
Distance covered in 10 minutes at 20 km/h =  Distance covered in 8 minutes at (20 + x) km
20*10/60 =  (20 + x) * 8/60
200 = 160 +  8x
x = 5 km/h

 

2. The distance between two cities A and B is 330km. A train starts from A at 8 (a)m. and travels towards B at 60 km/hr. Another train starts from B at 9 (a)m. and travels towards A at 75 km/hr. At what time do they meet?
1. 10 am.
2. 10 : 30 am.
3. 11 am.
4. 11 : 30 am.
5. None of these

Answer & Explanation

Answer:- 3

Explanation :-

Distance covered by first train in 1 hr = 60 km
Therefore , Distance covered by two trains at 9 A.M. = 330 – 60 = 270 km
Relative speed = 60 + 70 = 135 km/h
Time of meeting of Both the trains = 270/135 = 2 hrs
Therefore, Both trains meet at = 9 + 2 = 11 A.M.

 

3. Two trains are moving on two parallel tracks but in opposite directions. A person sitting in the train moving at the speed of 80 km/hr passes the second train in 18 seconds. If the length of the second train is 1000 m, its speed is?
1. 100 km/hr
2. 120 km/hr
3. 140 km/hr
4. 150 km/hr
5. None of these

Answer & Explanation

Answer:- 2

Explanation :-

Let the speed of the second train be  x km/h
Man’s speed = 80 km/h = 80 *5/18
According to question
1000/(x + (80*5)/18) = 18
1000 = 18x + 400
x = 600/18 m/s = (600/18)* (18/5) = 120 km/h

 

4. In covering a distance of 30 km, Abhay takes 2 hours more than Sameer. If Abhay doubles his speed, then he would take 1 hour less than Sameer. Abhay’s speed is?
1. 5 kmph
2. 6 kmph
3. 6.25 kmph
4. 7.5 kmph
5. None of these

Answer & Explanation

Answer:- 1

Explanation :-

Let Abhay’s speed = x km/h
Time = Distance / Speed
(30/x) – (30/2x) = 3
6x = 30
x = 5 km/h

 

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