Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?a)30b)40c)50d)60e)None of theseCorrect answer is option 'D'. Can you explain this answer?

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Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?

a)
30
b)
40
c)
50
d)
60
e)
None of these

Correct answer is option 'D'. Can you explain this answer?

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Verified Answer

Towns A and B are 200 km apart; A is in the South and B in the North. ...

The fact that the fly has flown equal distances North and South shows that its final position is the same as its initial position; the point where the trains meet is 80 km from A.
The train starting from A has a speed of 40 km/hr, so it takes 2 hours to reach this point.
The other train must also take 2 hours to reach this same point, which is (200 - 80 =) 120 km from B, so the speed of the second train is 120/2 = 60 km/hr.
Hence, option 4.

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Towns A and B are 200 km apart; A is in the South and B in the North. ...

Understanding the problem:
- Towns A and B are 200 km apart, with A in the South and B in the North.
- Trains start simultaneously from both A and B towards each other.
- The train starting from A has a speed of 40 km/hr.
- A fly is initially 80 km north of A.
- The fly starts flying towards the train starting from B as soon as the trains start.
- On reaching the train starting from B, the fly turns around and starts flying towards the train starting from A.
- The fly continues this behavior until the trains meet and it is squashed.
- At the time the trains meet, the fly has flown equal distances North and South.
- We need to determine the speed of the train starting from B.

Solution:
1. Let's assume the speed of the train starting from B is V km/hr.
2. The time taken by the train starting from A to meet the train starting from B is the same as the time taken by the fly to fly equal distances North and South.
3. Let the time taken be T hours.
4. Distance traveled by the train starting from A = Speed * Time = 40T km
5. Distance traveled by the fly northward = 80 km (given)
6. Distance traveled by the fly southward = 40T - 80 km (since it has to cover half the distance flown by the train)
7. Since the distances traveled northward and southward are equal, we have the equation: 80 = 40T - 80
8. Solving this equation, we get T = 4 hours.
9. The distance traveled by the train starting from A in 4 hours = 40 * 4 = 160 km
10. Since the total distance between the two towns is 200 km, the distance traveled by the train starting from B is 200 - 160 = 40 km.
11. Therefore, the speed of the train starting from B = Distance / Time = 40 km / 4 hours = 10 km/hr.

Therefore, the speed of the train starting from B is 10 km/hr, which is not among the given options. Hence, the correct answer is None of these.

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Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?

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Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?a)30b)40c)50d)60e)None of theseCorrect answer is option 'D'. Can you explain this answer? for CAT 2025 is part of CAT preparation. The Question and answers have been prepared according to the CAT exam syllabus. Information about Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?a)30b)40c)50d)60e)None of theseCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for CAT 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Towns A and B are 200 km apart; A is in the South and B in the North. There is only one railway track between them; on a certain day, trains start simultaneously from both A and B with different speeds towards each other. The train starting from A has a speed of 40 km/hr. A fly is initially 80 km north of A. As soon as the trains start, it starts flying towards the train initially at B; on reaching it, it immediately turns around and starts flying towards the other train, and turns around again on reaching it. It continues this behaviour till the trains meet and it is squashed. At the time that the trains meet, the fly has flown equal distances North and South. What is the speed (in km/hr) of the second train?a)30b)40c)50d)60e)None of theseCorrect answer is option 'D'. Can you explain this answer?.

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