Question

When will the hour and the minute hand of a clock first be together after 4 o'clock?
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Answer 1

Answer:

Answer. hence at 4:21:49.5 minutes hand exactly aligned with the hour hand

Answer 2

Answer:

At 4:00 the hands are 120° apart and are moving closer. The “big” hand advances 6° every minute, and the “little” hand advances 0.5° every minute, so the gap closes by 5.5° per minute.

120/5.5 = 21.818181… so it takes 21 and 9/11 of a minute. This works out to 4:21:49 + 1/11 of a second.