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:
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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