Problems on Clocks

Problems on Clocks

Learn and practice Problems on clocks with easy explaination and shortcut tricks. All questions and answers on clocks covered for various Competitive Exams

Solve Problems on clocks:

1) How many times the hands of a clock coincide in a day?

  1. 24
  2. 22
  3. 23
  4. 21
View Answer

The Correct answer is (B)

Explanation:

The hands of a clock coincide only once between 11 O’ clock and 1 O’ clock, so in every 12 hours, the hands of a clock will coincide for 11 times.

∴ In a day or 24 hours, the hands of a clock will coincide for 22 (11+11) times

2) At what time between 3 and 4, the hands of a clock are straight and point in opposite directions?

  1. 42min. past 3
  2. 45min. past 3
  3. 49min. past 3
  4. 51min. past 3
View Answer

The Correct answer is (C)

Explanation:

At 3 O’ clock, the hands of the clock are 15 minute spaces apart. To be in straight line and in opposite directions, the hands must be 30 minutes spaces apart.

Now, the minute hand is 15 minute spaces behind the hour hand, so it has to gain 45 (15+30) minute spaces over the hour hand.

55 minute spaces are gained in 60 minutes by the minute hand

45 minutes will be gained in =* 45 minutes

 =540/11

= 49 1/11 minutes past 3.

3) An accurate clock indicates 8 O’ clock in the morning. Through how many degrees the hour hand turns when the clock indicates 3 O’ clock in the afternoon?

  1. 210°
  2. 200°
  3. 190°
  4. 185°
View Answer

The Correct answer is (A)

Explanation:

There are 7 hours between 8 O’ clock in the morning and 3 O’ clock in the afternoon.

Now, angle traced by the hour hand in 12 hours = 360°

∴ Angle traced by the hour hand in 7 hours =360/12 * 7

=210°

4) What is the angle between hour hand and minute hand of a clock at 3.30?

  1. 65°
  2. 70°
  3. 75°
  4. 80°
View Answer

The Correct answer is (C)

Explanation:

Angle traced by the hour hand in 12 hours = 360°

Angle traced by the hour hand in 3 hours 30 minutes =360/12 * 3 + 30/60 hrs

=360/12 * 21/6  =105°

Angle traced by minute hand in 60 minutes = 360°

Angel traced by minute hand in 30 minutes ==360/12 * 30  =180° 

∴ Required angle would be = (180 – 105)° = 75°

Try to solve more problems on clocks.

5) At what time between 4 o’clock and 5 O’ clock will the hands of a clock coincide?

  1. 21minutes past 4
  2. 20minutes past 4
  3. 19minutes past 4
  4. 22minutes past 4
View Answer

The Correct answer is (A)

Explanation:

At 4 O’ clock, the minute hand is 20 minute spaces behind the hour hand. To coincide with the hour hand, it has to gain 20 minute spaces.

Now, 55 minute spaces are gained by the minute hand in 60 minutes

20 minutes will be gained in 60/55 * 20  =21 9/11 minutes 

∴ The hands will coincide at 21  9/11 minutes past 4.

6) A clock is set at 4am. It loses 16 minutes in 24 hours. What will be the correct time when the clock indicates 9pm on the 4th day?

  1. 8pm
  2. 7pm
  3. 10pm
  4. 11pm
View Answer

The Correct time is (C)

Explanation:

Time from 4am on a day to 9pm on the 4th day = 89 hours

As per the question, 23 hrs 44 minutes of this clock = 24 hours of the correct clock as this clock loses 16 minutes in 24 hours.

23 hrs 44 minutes =356/15 hrs

Now, 356/15 Hrs of this clock = 24 hours of correct clock

89 hours of this clock =( 24*15 /356) * 89 = 90 hours of the correct clock, i.e. the correct clock gains one hour over the incorrect clock.

∴The correct time on the fourth day would be 10pm.

Try to solve more problems on clocks.

7) How much does a watch lose per day, if its hands coincide every 63 minutes?

  1. 56min.
  2. 57min.
  3. 55min.
  4. 54min.
View Answer

The Correct answer is (A)

Explanation:|

The hands of a clock coincide once after 65 5/11 minutes in every hour.

As per question, the hands coincide in every 63 minutes.

Therefore, the loss in 63 minutes = 65 5/11 -63

=720/11 – 63

=(720-693)/11

=27/11 minutes

Now, loss in 63 minutes = 27/11 minutes

∴ Loss per day or in 24 hours==27/11 * 1/63 *(24*60) minutes

=4320/77 

=56 8/77 minutes

8) At what time between 4:30 and 5:00 will the hands of a clock be at right angle?

  1. 35min. past 4
  2. 37min. past 4
  3. 38min. past 4
  4. 39min. past 4
View Answer

The Correct answer is (C)

Explanation:

As we know, the hands of a clock will be at 90° between H: 30 and (H+1) O’clock at (5H + 15) 12/11 minutes past H O’ clock.

∴ Required time = (5H + 15) 720/11

Now, H = 4

= (5*4 + 15) 720/11
= 20 + 15 * 720/11

=35 * 12/11

=420/11

=38 2/11 minutes past 4

Try to solve more problems on clocks.

9) A watch which gains uniformly is 5 minutes slow at 6am on Monday and is 5 minutes 48 seconds fast at 6pm on the following Monday. When was it correct?

  1. 5:20 pm on Wednesday
  2. 5:20 pm on Thursday
  3. 4:20 pm on Wednesday
  4. 4:20 pm on Thursday
View Answer

The Correct answer is (B)

Explanation:

Time from 6am on Monday to 6pm on following Monday = 7 days and 12 hours, i.e. 24*7 + 12 = 180 hours

So, the watch gains 5+ 5 48/60 =54/5 minutes in 180 hours

Now, 54/5 minutes are gained in 180 hours

∴ 5 minutes will be gained in 180 * 5/54 * 5 = 250/3 =83 1/3  hours or 83 hours 20 minutes.

83 hour 20 minutes = 3 days (72 hours) 11 hours 20 minutes

Therefore, the watch was correct 3 days 11 hours 20 minutes after 6am on Monday, i.e. it was correct at 20 minutes past 5pm on Thursday.

10) At what times between 5 O’ clock and 6 O’ clock the hands of a clock are 10 minute spaces apart?

clock
View Answer

The Correct answer is (A)

Explanation:

Between 5 O’ clock and 6 O’ clock, the hands will be 10 minutes spaces apart twice, i.e. when the minute hand is 10 minute spaces behind the hour hand and when the minute hand is 10 minute space ahead of the hour hand.

Case 1: When the minute hand is 10 minutes spaces behind the hour hand;

At 5 O’ clock, the minute hand is 25 minute spaces behind the hour hand.

So, the minute hand has to gain (25-10) = 15 minute spaces over hour hand to be 10 minute spaces apart.

Now, 55 minute spaces are gained in 60 minutes.

15 minute spaces will be gained in * 15 = 16  4/11 minutes

∴The hands of the clock will be 10 minute spaces apart at 16  4/11 minutes past 5.

Case 2: When the minute hand is 10 minute spaces ahead of the hour hand.

The minute hand has to gain (25 + 10) = 35 minute spaces over the hour hand.

Now, 55 minutes are gained in 60 minutes.

35 minutes will be gained in * 35 = 38  2/11 minutes

∴ The hands of the clock will be 10 minute spaces apart at 38 2/11minutes past 5.

Leave a Reply