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- Question
Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.
Options- A. 12 sec
- B. 24 sec
- C. 48 sec
- D. 60 sec
- Correct Answer
- 24 sec
ExplanationRelative speed = = (45 + 30) km/hr = ❨ 75 x 5 ❩ m/sec 18 = ❨ 125 ❩ m/sec. 6 We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.
So, distance covered = Length of the slower train.
Therefore, Distance covered = 500 m.
∴ Required time = ❨ 500 x 6 ❩ = 24 sec. 125 - 1. A train travelling at 48 kmph completely crosses another train having half its length and travelling in opposite direction at 42 kmph, in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is
Options- A. 400 m
- B. 450 m
- C. 560 m
- D. 600 m Discuss
- 2. A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is:
Options- A. 48 km/hr
- B. 54 km/hr
- C. 66 km/hr
- D. 82 km/hr Discuss
- 3. Jar A has 36 litres of mixture of milk and water in the respective ratio of 5 : 4. Jar B which had 20 litres of mixture of milk and water, was emptied into jar A, and as a result in jar A, the respective ratio of milk and water becomes 5: 3. What was the quantity of water in jar B?
Options- A. 5 lit
- B. 3 lit
- C. 8 lit
- D. 2 lit Discuss
- 4. A mixture contains spirit and water in the ratio of 3 : 2. If it contains 3 litres more spirit than water, the quantity of spirit in the mixture is
Options- A. 12 litres
- B. 10 litres
- C. 9 litres
- D. 8 litres Discuss
- 5. In what ratio must a mixture of 20% milk strength be mixed with that of 60% milk strength so as to get a new mixture of 25% milk strength?
Options- A. 7 : 1
- B. 4 : 1
- C. 5 : 2
- D. 9 : 2 Discuss
- 6. Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Options- A. 1 : 3
- B. 3 : 2
- C. 3 : 4
- D. None of these Discuss
- 7. A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is:
Options- A. 45 m
- B. 50 m
- C. 54 m
- D. 72 m Discuss
- 8. Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:
Options- A. 30 km/hr
- B. 45 km/hr
- C. 60 km/hr
- D. 75 km/hr Discuss
- 9. A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?
Options- A. 65 sec
- B. 89 sec
- C. 100 sec
- D. 150 sec Discuss
- 10. A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?
Options- A. 3.6 sec
- B. 18 sec
- C. 36 sec
- D. 72 sec Discuss
Problems on Trains
Search Results
Correct Answer: 400 m
Explanation:
Let the length of the first train be x meters.
| Then, the length of the second train is | ❨ | x | ❩ | meters. |
| 2 |
| Relative speed = (48 + 42) kmph = | ❨ | 90 x | 5 | ❩ | m/sec = 25 m/sec. |
| 18 |
| ∴ | [x + (x/2)] | = 12 or | 3x | = 300 or x = 200. |
| 25 | 2 |
∴ Length of first train = 200 m.
Let the length of platform be y meters.
| Speed of the first train = | ❨ | 48 x | 5 | ❩ | m/sec = | 40 | m/sec. |
| 18 | 3 |
| ∴ (200 + y) x | 3 | = 45 |
| 40 |
⟹ 600 + 3y = 1800
⟹ y = 400 m.
Correct Answer: 82 km/hr
Explanation:
Let the speed of the second train be x km/hr.
| Relative speed | = (x + 50) km/hr | |||||||
|
||||||||
|
Distance covered = (108 + 112) = 220 m.
| ∴ | 220 | = 6 | ||
|
⟹ 250 + 5x = 660
⟹ x = 82 km/hr.
Correct Answer: 5 lit
Explanation:
Jar A has 36 litres of mixture of milk and water in the respective ratio of 5 : 4 => Quantity of milk in Jar A = 5/9 x 36 = 20 litres Quantity of water in Jar A = 36 - 20 = 16 litres Let quantity of water in Jar B = x litres => Quantity of milk in Jar B = (20 - x) litres Acc. to ques, =>[20 + (20-x)]/(16+x) = 5/3 => 120?3x = 80+5x => 5x +3x = 120?80 => 8x = 40 => 5 litres.
Correct Answer: 9 litres
Explanation:
Ratio of milk and water = 2 : 1
Quantity of milk = 60 X 2/3 = 40 litre
Quantity of water = 20 litre
To make ratio, 1: 2, we have to double the water that of milk
So, water should be 80 litre.
That means 80 ? 20 = 60 litre water to be added.
Correct Answer: 7 : 1
Explanation:
Ratio of milk and water = 2 : 1
Quantity of milk = 60 X 2/3 = 40 litre
Quantity of water = 20 litre
To make ratio, 1: 2, we have to double the water that of milk
So, water should be 80 litre.
That means 80 ? 20 = 60 litre water to be added.
Correct Answer: 3 : 2
Explanation:
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27x metres,
and length of the second train = 17y metres.
| ∴ | 27x + 17y | = 23 |
| x+ y |
⟹ 27x + 17y = 23x + 23y
⟹ 4x = 6y
| ⟹ | x | = | 3 | . |
| y | 2 |
Correct Answer: 50 m
Explanation:
| 2 kmph = | ❨ | 2 x | 5 | ❩ | m/sec = | 5 | m/sec. |
| 18 | 9 |
| 4 kmph = | ❨ | 4 x | 5 | ❩ | m/sec = | 10 | m/sec. |
| 18 | 9 |
Let the length of the train be x metres and its speed by y m/sec.
| Then, | ❨ | x | ❩ | = 9 and | ❨ | x | ❩ | = 10. |
|
|
∴ 9y - 5 = x and 10(9y - 10) = 9x
⟹ 9y - x = 5 and 90y - 9x = 100.
On solving, we get: x = 50.
∴ Length of the train is 50 m.
Correct Answer: 60 km/hr
Explanation:
Let the speed of the slower train be x m/sec.
Then, speed of the faster train = 2x m/sec.
Relative speed = (x + 2x) m/sec = 3x m/sec.
| ∴ | (100 + 100) | = 3x |
| 8 |
⟹ 24x = 200
| ⟹ x = | 25 | . |
| 3 |
| So, speed of the faster train = | 50 | m/sec |
| 3 |
| = | ❨ | 50 | x | 18 | ❩km/hr |
| 3 | 5 |
= 60 km/hr.
Correct Answer: 89 sec
Explanation:
| Speed = | ❨ | 240 | ❩m/sec = 10 m/sec. |
| 24 |
| ∴ Required time = | ❨ | 240 + 650 | ❩sec = 89 sec. |
| 10 |
Correct Answer: 36 sec
Explanation:
Speed of train relative to jogger = (45 - 9) km/hr = 36 km/hr.
| = | ❨ | 36 x | 5 | ❩m/sec |
| 18 |
= 10 m/sec.
Distance to be covered = (240 + 120) m = 360 m.
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