**Basic Concept of Clock **

**In an aptitude test, you will get questions based on concepts of Clock. Wherein the concept is based on movement of Hour hand and Minute hand.**

A clock is a complete circle having 360 degrees, which is equally divided into 12 parts i.e. each part is 360/12 = 30°.

The minute hand rotates through 360 degrees to complete round in one hour.

Angle traced by minute hand in 60 min. = 360°.

In 1 minute it covers 360/60 = 6° per minute.

Angle traced by hour hand in 12 hrs = 360°

The hour hand covers 30° in 60 minutes i.e. ½° per minute.

Both the hands of a clock coincide once in every hour.

The hands of a clock will be in straight line but opposite in direction, 22 times in a day.

The hands of a clock coincide 22 times in a day and become straight 44 times in a day.

The hands of a clock are at right angles 44 times in a day.

**We will use these concepts while solving problems on clocks.**

**Clock Questions With Answers**

**Q1) An accurate clock shows 8 o'clock in the morning. Through how may degrees will the hour hand rotate when the clock shows 2 o'clock in the afternoon?**

A) 154°

B) 170°

C) 160°

D) 180°

**Solution:**

**Q2) A clock is started at noon. By 10 minutes past 5, the hour hand has turned through**

A) 145°

B) 152°

C) 155°

D) 140°

**Solution :**

**Q3) At what time between 7 and 8 o'clock will the hands of a clock be in the same straight line but not together?**

A) 5(1/11) minutes past 7

B) 5 minutes past 7

C) 5(3/11) minutes past 7

D) 5(5/11) minutes past 7

**Solution: **

**Q4) At what time between 5.30 and 6 will the hands of a clock be at right angles?**

A) 44(7/11) minutes past 5

B) 43 minutes past 5

C) 43(7/11) minutes past 5

D) 44 minutes past 5

**Solution :**

**Q5) An accurate clock shows 8 o'clock in the morning. Through how may degrees will the hour hand rotate when the clock shows 2 o'clock in the afternoon? **

A. 144°

B. 150°

C. 168°

D. 180°

**Solution : **

**Q6) The reflex angle between the hands of a clock at 10.25 is: **

A) 180°

B) 192(1/2)°

C) 195°

D) 192(1/2)°

**Solution :**

**Q7) 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°

**Solution :**

Angle traced by hour hand in 5 hrs 10 min. i.e.,

**Q8) A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o'clock, the true time is: **

A) 5 PM

B) 4 PM

C) 58(7/11)min. past 3

D) None Of These

**Solution : **

3 min. 5 sec. of this clock = 3 min. of the correct clock.

37 / 720 hrs of this clock = 3 min. of the correct clock.

=> 37/ 720 hrs of this clock = 1/ 20 hrs of the correct clock.

=> 37 / 4 hrs of this clock = (1/20 x 720/37 x 37/4) hrs of the correct clock

= 9 hrs of the correct clock.

The correct time is 9 hrs after 7 a.m. i.e., 4 p.m.

**Q9) At what time between 7 and 8 o'clock will the hands of a clock be in the same straight line but, not together? **

A) 5 min. past 7

B) 5 (2/11) min. past 7

C) 5 (3/11) min. past 7

D) 5 (5/11) min. past 7

**Solution : **

At 7 o'clock, they are 25 min. spaces apart.

Minute hand will have to gain only 5 min. spaces.

55 min. spaces are gained in 60 min.

5 min. spaces are gained in (60/55 x 5)min = 5 (5/11) min.

Required time = 5 (5/11) min. past 7.

**Q10) At what time between 5.30 and 6 will the hands of a clock be at right angles? **

A) 43 (5/11) min. past 5

B) 43 (7/11) min. past 5

C) 40 min. past 5

D) 45 min. past 5

**Solution:**

To be at right angles and that too between 5.30 and 6, the minute hand has to gain (25 + 15) = 40 min. spaces.

55 min. spaces are gained in 60 min.

40 min. spaces are gained in (60/55 x 40) min = 43(7/11)min.

Required time = 43 (7/11) min. past 5.