Distance by which X defeats Y: X runs 1 km in 8 min 40 s, Y runs 1 km in 10 min. By what distance does X defeat Y?

Introduction / Context:
Compare distances covered by Y in the time X takes to finish 1 km to get the winning margin.

Given Data / Assumptions:

• X's 1 km time = 520 s
• Y's 1 km time = 600 s

Concept / Approach:
Distance(Y in 520 s) = (1000/600)*520. Subtract from 1000 m to get X’s winning distance.

Step-by-Step Solution:

Verification / Alternative check:
Speeds: v_X = 1000/520; v_Y = 1000/600. Margin in 520 s equals (v_X − v_Y)*520 = same 133 1/3 m.

Why Other Options Are Wrong:
133 2/3 m differs by 1/3 m; others are far off.

Common Pitfalls:
Converting minutes to seconds incorrectly; mixing up who is faster.

Final Answer:
1331/3 m