Puzzle 1: How many times in a day, are the hands of a clock in straight line but opposite in direction?
A) 20 B) 22
C) 24 D) 48
Answer: 22
Explanation: The hands of a clock point in opposite directions (in the same straight line) 11 times in every 12 hours. (Because between 5 and 7 they point in opposite directions at 6 o’clock only).
So, in a day, the hands point in the opposite directions 22 times.
Puzzle 2: A clock is started at noon. By 10 minutes past 5, the hour hand has turned through:
A) 145 B) 150
C) 155 D) 160
Answer: 155
Explanation: Angle traced by hour hand in 12 hrs. = 360°.
Angle traced by hour hand in 5 hrs. 10 min. i.e. 31/6 hrs. = [(360/12) x (31/6)]° 155°
Puzzle 3: A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct?
A) 2 p.m. on Tuesday B) 2 p.m. on Wednesday
C) 3 p.m. on Thursday D) 1 p.m. on Friday
Answer: 2 p.m. on Wednesday
Explanation: Time from 12 p.m. on Monday to 2 p.m. on the following Monday = 7 days 2 hours = 170 hours.
∴ The Watch gains [2 + 4 (4/5)] min. or 34/5 in 170 hrs.
Now, 34/5 min. are gained in 170 hrs.
∴ 2 min. are gained in (170 x (5/34) x 2) hrs = 50 hrs
∴ Watch is correct 2 days 2 hrs. After 12 p.m. on Monday i.e., it will be correct at 2 p.m. on Wednesday
Puzzle 4: At 3.40, the hour hand and the minute hand of a clock form an angle of:
A) 120 degrees B) 125 degrees
C) 130 degrees D) 135 degrees
Answer: 130 degrees
Explanation: Angle traced by hour hand in 12 hrs. = 360°.
Angle traced by it in 11/3 hrs = [(360/12) x (11/3)]° = 110°
Angle traced by minute hand in 60 min. = 360º.
Angle traced by it in 40 min. = [(360/60) x 40]° = 240°
∴ Required angle (240 – 110)° = 130°.
Puzzle 5: How many minutes is it until six o’clock if fifty minutes ago it was four times as many minutes past three o’clock?
Answer: Twenty-six minutes.