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Sunday, April 2, 2017

Clock Puzzle 5 [With Answers]

Puzzle 1: How many times do the hands of a clock coincide in a day?

A) 20         B) 21

C) 22         D) 24

Answer: Option 'C'

Explanation: The hands of a clock coincide 11 times in every 12 hours (Since between 11 and 1, they coincide only once, i.e. at 12 o'clock).

The hands coincide 22 times in a day.

Puzzle 2: How many times are the hands of a clock at right angles in a day?

A.) 22            B.) 44

C.) 38            D.) 48

Answer: Option 'B'

Explanation: In 12 hours, they are at right angles 22 times.

In 24 hours, they are at right angles 44 times.

Puzzle 3: How much does a watch lose per day, if its hands coincide every 64 minutes?

A) 32 8/11min            B) 36 5/11min

C) 90min                    D) 96min

Answer: Option 'A'

Explanation: 55 min. spaces are covered in 60 min.

60 min spaces are covered in (60/55 * 60) min = 65 5/11 min

Loss in 64 min = (65 5/11- 64) = 16/11 min

Loss in 24 hrs = (16/11 * 1/64 * 24 * 60) min

= 32 8/11 min

Puzzle 4: How many times in a day the hands of a clock are straight?

A) 22              B) 21

C) 43              D) 44

Answer: Option 'D'

Explanation: In 12 hours, the hands coincide or are in opposite direction 22 times.

In 24 hours, they are at right angles 22 times.

Puzzle 5: At what time between 4 & 5 will the hands of a watch point in opposite directions? 

A) 43 min past 4                    B) 42 5/11 min past 4

C) 50 4/11 min past 4            D) 40 min past 4

Answer: Option 'C'

Explanation: At 4 o'clock, the hands of the watch are 20 min. spaces apart.

To be in opposite directions, they must be 30min. spaces apart.

Minute hand will have to gain 5 min. spaces.

55min spaces are gained in 60 min.

5 min. spaces are gained in (60/55 * 50) min. or 54 6/11 min.

Required time = 54 6/11 min. past 4.

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