In an accurate clock, how many degrees does the minute hand move in a period of 2 hours 20 minutes?

Introduction / Context:
The minute hand completes a full circle (360°) each hour. Equivalently, it turns at 6° per minute. Converting the total time into minutes lets us multiply directly to find degrees swept.

Given Data / Assumptions:

• Total time = 2 h 20 min = 140 minutes.
• Minute hand speed = 6° per minute.

Concept / Approach:
Degrees moved = minutes elapsed * 6°/minute.

Step-by-Step Solution:

Verification / Alternative check:
2 hours = 720° (two full turns) and 20 minutes = 120°; total 720° + 120° = 840°.

Why Other Options Are Wrong:
520° and 320° undercount; 140° incorrectly treats 1° per minute; none equals the correct combined sweep.

Common Pitfalls:
Using 360°/hour without converting the “20 minutes” part, or mixing the hour hand’s 0.5°/minute rate.

Final Answer:
840°.