Two cars start at the same time from towns A and B which are 240 km apart. Car X travels from A to B at 55 km/h, Car Y from B to A at 70 km/h. After how many hours will they meet?
Answer
1.92 hours (1 hour 55 minutes)
The correct answer is 1.92 hours (1 hour 55 minutes) — Thus they meet after about 1 hour 55 minutes.
Step-by-step solution
- When moving towards each other, the relative speed is the sum of their speeds: 55 + 70 = 125 km/h.
- Use time = distance ÷ relative speed: 240 km ÷ 125 km/h = 1.92 hours.
- Convert 0.92 hours to minutes: 0.92 × 60 ≈ 55 minutes.
- Thus they meet after about 1 hour 55 minutes.
Common mistake: Using average speed instead of sum of speeds for relative motion
Concept tested: Relative speed of two moving objects
Published · How this solution was prepared and checked
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