Concept of Clocks: 

Basically, in a clock we have three hands (Hour’s hand, Minutes hand and Seconds hand).

Hour’s hand covers 30 degrees for every one hour and 1/2 degree for every one minute. Minutes hand covers 6 degrees for every one minute.

Concept 1:

Finding the Angle between the Hands of a Clock.

Eg: 1) How many times in a day, the hands of a clock are straight?

(a) 22                (b) 24                            (c) 44                            (d) 48

Concept 2:

Finding the Time, when Angle between the Hands are given.

1) At what time between 2 and 3 o’clock will the hands of a clock be together?

(a) 10 10/11  min. past 2            (b) 5 10/11 min. past 2

(c) 10 5/11  min. past 2              (d) 5 5/11          (e) None of these

Concept 3:

Identifying the Clock is moving Fast or Slow.

 Identify whether the clock is moving faster or slower based on the information given in the problem.

In general, the two hands of clock cross each other after every  65 5/11 minutes. In case, if the hands of a clock cross each other after 65 5/11 then it means that clock is moving slow. If the hands of a clock cross each other before 65 5/11, then it means that clock is moving faster.

Eg: 1) A watch which gains uniformly is 2 minutes slow 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

Concept 4:

Finding the Actual Time or Mirror Time

In this concept, the candidate has to find the Actual time or else Mirror time when one of the value is given. According to the concept of Clocks, Actual Time + Mirror Time = 12 hours.

Eg: What is the mirror time, if the actual time is shows that 5:30?

In 12 minutes, how many degrees does the minute hand gain over the hour hand?

A) 88 degrees             B) 66 degrees              C) 80 degrees              D) 74 degrees      E) 64 degrees

SOLUTION:

In 60 minutes, the minute hand gains 330 degrees over the hour hand.

60 mins = 330 degrees

12 mins = ?

? = (330 × 12) / 60

? = 66 degrees

Therefore, in 12 minutes, the minute hand gains over the hour hand by 66 degrees.

ANSWER: B

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