Two trains start at the same time form A and B and proceed toward each other at the speed of 75 km/hr and 50 km/hr respectively. when both meet at a point in between, one train was found to have travelled 175 km more than the other. Find the distance between A and B.
Aptitude
Problems on Trains
Difficulty: Medium
Choose an option
-
A875 km
-
B785 km
-
C758 km
-
D857 km
Answer
Correct Answer: 875 km
Explanation
### Concept & Logic
When two objects travel for the same duration, the difference in distance covered is equal to the product of their speed difference and the time traveled.
$$ \text{Distance Difference} = (\text{Speed}_1 - \text{Speed}_2) \times \text{Time} $$
### Step-by-Step Solution
1. **Identify Given Values:**
- Speed 1 = 75 km/hr.
- Speed 2 = 50 km/hr.
- Distance difference = 175 km.
2. **Calculate Speed Difference:**
- $75 - 50 = 25$ km/hr.
3. **Find Travel Time:**
- Time ($T$) = $\frac{175}{25} = 7$ hours.
4. **Calculate Total Distance:**
- Relative speed = $75 + 50 = 125$ km/hr.
- Total distance = $\text{Relative Speed} \times T = 125 \times 7 = 875$ km.
### Exam Strategy & Shortcut
Instead of solving for individual distances, find the time they took to create the 175 km gap ($175 / 25 = 7$), then multiply that exact time by the sum of their speeds to get the total distance instantly.
### Common Pitfall
Multiplying the time by the individual speeds instead of the relative speed when attempting to find the total distance between the two stations.
### Final Answer
Therefore, the correct answer is **875 km**.