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Friday, February 24, 2017

Clock Puzzles 4 [With Answers]

Clock Puzzle

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.

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