X and Y start walking toward each other at 8:00 am from points 17.5 km apart. Their speeds are 3 km/h and 4 km/h, respectively. At what time do they meet?

Introduction / Context:
When two people move toward each other on a line, the closing speed is the sum of their speeds. Divide the initial separation by the closing speed to get the meeting time from the start.

Given Data / Assumptions:

• Distance apart = 17.5 km.
• Speeds: 3 km/h and 4 km/h.
• Start time = 8:00 am.

Concept / Approach:
Relative (closing) speed = 3 + 4 = 7 km/h. Time to meet = distance / relative speed.

Step-by-Step Solution:

Verification / Alternative check:
Positions after 2.5 h: X covers 7.5 km, Y covers 10 km; total 17.5 km—consistent.

Why Other Options Are Wrong:
Evening times are impossible here; 11:30 am implies 3.5 hours instead of 2.5.

Common Pitfalls:
Using the difference of speeds instead of the sum for opposite directions.

Final Answer:
10 : 30 am