At what time between 10 am and 11 am will the angle between the minute hand…
20232023
At what time between 10 am and 11 am will the angle between the minute hand and the hour hand be 3° (assuming the hour hand is closer to 12 than the minute hand)?
- A.
10:52
- B.
10:53
- C.
10:54
- D.
10:55
Attempted by 3 students.
Show answer & explanation
Correct answer: C
Concept: On an analog clock measured clockwise from 12, the hour hand's angle is (30H + 0.5M)° and the minute hand's angle is (6M)° for a time of H hours and M minutes. The angle between the hands equals the absolute difference between these two values, and whichever hand's angle value is larger sits closer to the upcoming 12 mark.
Step-by-step:
Let the required time be 10 hours and x minutes, with 10 ≤ time < 11.
Hour-hand angle = 30(10) + 0.5x = 300 + 0.5x.
Minute-hand angle = 6x.
Since the hour hand is given to be the one closer to 12, its angle value must be the larger of the two, so (300 + 0.5x) − 6x = 3.
Simplify: 300 − 5.5x = 3, so 5.5x = 297, giving x = 54.
So the required time is 10:54.
Cross-check: At 10:54, hour-hand angle = 300 + 0.5(54) = 327°, and minute-hand angle = 6(54) = 324°. The difference is exactly 3°, and 327° is the larger value, confirming the hour hand is the one nearer the 12 mark — both conditions in the question are satisfied.
Answer: 10:54.