Q179
ReasoningCalendar & Clocks
How many times do the hands of a clock coincide in a day?
- a.24
- b.20
- c.21
- d.22
Answer: (D) 22
The hour and minute hands coincide 11 times in every 12 hours, not 12, because the coincidence expected between 11 o'clock and 1 o'clock occurs just once, at exactly 12:00; so in a day (24 hours) they coincide 22 times, once every $65\frac{5}{11}$ minutes. Related facts: the hands point in exactly opposite directions 22 times a day, are at right angles 44 times a day, and lie in a straight line (together or opposite) 44 times a day.