Question

Two persons ride towards each other from two places 55 km apart, one riding at 12 km/h and the other at 10 km/h. When will they be 11 km apart?

• A. 2 h and 30 min
• B. 1 h and 30 min
• C. 2 h
• D. 2 h and 45 min

Hint:

For objects moving towards each other, relative speed is the sum of speeds. Remember to consider both before and after meeting.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Relative speed when moving towards each other is the sum of speeds.

Step 2: Detailed Explanation:
Total distance = 55 km. They will be 11 km apart either before meeting (distance covered = 55 - 11 = 44 km) or after meeting (distance covered = 55 + 11 = 66 km).
Relative speed = \(12 + 10 = 22\) km/h.
Time to cover 44 km = \(\frac{44}{22} = 2\) hours.
Time to cover 66 km = \(\frac{66}{22} = 3\) hours.
The earliest time they are 11 km apart is 2 hours.

Step 3: Final Answer:
They will be 11 km apart after 2 hours.