Find the angle between the hour and minute hands at 6:30 a.m.

Difficulty: Easy

Correct Answer: 15°

Explanation:


Introduction / Context:
We compute the smaller angle between the hour and minute hands at a specified time.



Given Data / Assumptions:

  • Time: 6:30 a.m.
  • Minute hand speed: 6 degrees per minute.
  • Hour hand speed: 0.5 degrees per minute.


Concept / Approach:
The minute hand angle from 12 at t minutes is 6t. The hour hand angle at h:t is 30h + 0.5t. The absolute difference gives the angle; choose the acute one if two are possible.



Step-by-Step Solution:
At 6:30, minute angle = 6 * 30 = 180°.Hour angle = 30*6 + 0.5*30 = 180 + 15 = 195°.Difference = |195 − 180| = 15°.



Verification / Alternative check:
General formula for angle at h:m is |30h − 5.5m|; substituting 6:30 → |180 − 165| = 15°, matches.



Why Other Options Are Wrong:
22.5° is the angle between hour positions at quarter intervals in some cases, not here. 25° is arbitrary. “None of these” is unnecessary since 15° fits.



Common Pitfalls:
Forgetting the hour hand advances between hours (the 0.5m term).



Final Answer:
15°

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