Race timing from lead (repeat form): In a 300 m race, A defeats B by 15 m or 5 s. Determine A’s time over the course.

Introduction / Context:Same structure as a classic race-time conversion problem: translate B's shortfall (distance and seconds) into B's speed and compute the shared finish time.

Given Data / Assumptions:

• Total race = 300 m
• B is 15 m behind at A's finish
• 15 m = 5 s for B

Concept / Approach:The finish time for A equals the time B took to run 285 m at 3 m/s.

Step-by-Step Solution:

Verification / Alternative check:In 95 s, B covers 285 m, 15 m behind the finish.

Why Other Options Are Wrong:They contradict the given 15 m in 5 s relationship for B.

Common Pitfalls:Using 300 m for B in the shared time instead of 285 m.

Final Answer:95 seconds