Clocks

12
 Question 1
In a clock, the time is 3.25.What is the angle between the hour hand and the minute hand of the clock:
 A 95/2 degrees B 90/3 degrees C 94/3 degrees D 95/3 degrees
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Question 1 Explanation:
As, the hour hand covers 360 degrees in 12 hrs. In the clock the time is 3.25 = 3 hrs 25 min = 41/12 hrs. So, the angle traced by hour hand = (360/12 x 41/12) degrees = 205 degrees. The minute hand covers 360 degrees in 60 minutes. So, the angle is traced by minute hand in 25 min = (360/60 x 25) degrees = 150 degrees. Hence, the required angle of the clock = (150- 205/2) degrees = 95/2 degrees.
 Question 2
A clock gains uniformly 5 min slow at 8 o’clock in the morning on Sunday and 5 min 48 sec fast at 8 pm on following Sunday. The correct time and day are:
 A 21 min past 7 pm and Wednesday B 20 min past 7 pm and Thursday C 21 min past 7 pm and Thursday D 20 min past 7 pm and Wednesday
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Question 2 Explanation:
The given time from 8:00 am on Sunday to 8 pm on following Sunday = 7 days 12 hrs = 180 hrs. So, the clock gains = (5 + 29/5)min = 54/5 min in 180 hrs. Hence, 5 min are gained in (180 x 5/54 x 5)hrs = 83 hrs 20 min = 3 days 11 hrs 20 min. The clock is correct 3 days 11 hrs 20 min after 8 am of Sunday. So, the correct time and day will be 20 min past 7 pm on Wednesday.
 Question 3
Sam sets alarm at 5 am. But the clock loses 16 minutes in 24 hours. Effectively, the clock indicates 10:00 pm on the 4th day. Find out the original time of the clock:
 A 9 pm B 10 pm C 11 pm D 08 pm
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Question 3 Explanation:
From the given information the time from 5 am on a day to 10 pm on the 4th day is 89 hrs. So, 23 hrs 44 min of this clock = 24 hrs of correct clock. Hence, 356/15 hrs of this clock = 24 hrs of correct clock. 89 hrs of the clock = (24 x 15/356 x 89)hrs of correct clock = 90 hrs of correct clock. Hence, the original time will be 11 pm.
 Question 4
The time of a clock is 8 am. Suddenly the clock gains 10 minutes in 24 hours. Find out the original time if the time of the clock is 1 pm on the following day:
 A 48 minutes past 12 B 47 minutes past 10 C 48 minutes past 11 D 48 minutes past 11
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Question 4 Explanation:
From 8 am on a day to 1 pm on the following day will be 29 hrs. So, the clock gains 10 min in 24 hours = 24 hrs of the correct time. Hence, 145/6 hrs of the clock = 24 hrs of the correct clock. 29 hrs of the clock = (24 x 6/145 x 24)hrs of the correct clock = 28 hrs 48 min of the correct clock. The correct time = 28 hrs 48 min after 8 am. Hence, the original time is 48 minutes past 12.
 Question 5
A time of a clock is set 3.40. Find out the angle that is formed by both hour hand and minute hand:
 A 120 degrees B 135 degrees C 140 degrees D 130 degrees
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Question 5 Explanation:
The hour hand covers the angle 360 degrees in 12 hrs. So, the angle is covered by it in 11/3 hrs = (360/2 x 11/3) degrees = 110 degrees . The minute hand covers the angle in 360 degrees in 60 min. So, the angle is covered by it in 40 min = (360/60 x 40) degrees = 240 degrees . Hence, the required angle made by both hands = (240 - 110) degrees = 130 degrees .
 Question 6
A clock shows 8:00 AM. When it is 2:00 PM, by what degree the hour hand rotates?
 A 145º B 160º C 180º D 175º
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Question 6 Explanation:
For 6 hrs duration hrs hand covered 6 hrs out of 12 hrs
When hrs hand covers 12 hrs it rotates for 360 degree
----------------------------6 --------------------- = (360/12)*6 = 180 degrees
 Question 7
A clock shows 10:00 AM. When it is 4:00 PM, by what degree the hour hand rotates?
 A 140º B 152º C 175º D 180º
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Question 7 Explanation:
For 6 hrs duration hrs hand covered 6 hrs out of 12 hrs When hrs hand covers 12 hrs it rotates for 360 degree ----------------------------6 --------------------- = 360/12)*6 = 180 degrees
 Question 8
A clock shows 10:00 AM. When it is 10:00 PM, by what degree the hour hand rotates?
 A 180 B 175 C 240 D 360
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Question 8 Explanation:
For 6 hrs duration hrs hand covered 12 hrs out of 12 hrs When hrs hand covers 12 hrs it rotates for 360 degree ----------------------------12 --------------------- =(360/12)*12 = 360 degrees
 Question 9
A clock shows 10:00 AM. What time it will be showing, if hrs hand rotates for 180 degrees?
 A 1:00 PM B 6:00 PM C 4:00 PM D 10:00 PM
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Question 9 Explanation:
When hrs hand rotates for 360 degree it covers 12 hrs --------------------------------- 180 --------------------- 6 hrs So the time will be: 10:00 AM + 6 hrs = 4:00 PM
 Question 10
A clock shows 06:00 AM. What time it will be showing, if hrs hand rotates for 360 degrees?
 A 4:00 AM of next day B 06:00 PM C 04:00 PM D 10:00 PM
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Question 10 Explanation:
When hrs hand rotates for 360 degree it covers 12 hrs --------------------------------- 360 --------------------- 12 hrs So the time will be: 06:00 AM + 12 hrs = 06:00 PM
There are 18 questions to complete.
12

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