Logical reasoning Clock concepts notes-CSEET
Logical reasoning Clock concepts:
ICSI CSEET: The Council of the ICSI has released a notice regarding CSEET on the day of the inauguration of ICSI Golden Jubilee Celebrations on 4th Oct 2017.
The Gazette Notification on the Company Secretaries (Amendment) Regulations, 2020 has been published on 3rd February 2020 in the Official Gazette of India and the same shall be applicable from the said date of publication.
Now ICSI Published a notice regarding CSEET Test which going to start from 2020 May.
We are now going to discuss the details of CSEET Paper-2 Legal Aptitude and Logical Reasoning – Logical reasoning Clock concepts notes.
Logical reasoning Clock concepts:
- The dial of the clock is circular in shape and was divided into 60 equal minute spaces
- 60 minute spaces traces an angle of3600. Therefore, 1 minute space traverses an angle of 60
- In 1 hour, Minute hand traverses 60 minute space or 3600 , Hour hand traverses 5 minute space or 300
- The hands of the clock are perpendicular in 15 minute spaces apart
- The hands of the clock are in straight line and opposite to each other in 30 minute spaces apart.
- The hands of the clock are in straight line when they coincide or opposite to each other.
- The hands of the clock are perpendicular to each other for 22 times in 12 hours and for 44 times in a day.
- The hands of the clock are opposite to each other for 11 times in 12 hours and 22 times in a day.
- The hands of the clock coincides with each other for 11 times in 12 hours and 22 times per day
- The hands of the clock are 44 times in a straight line per day
- The minute hand gain 55 minutes over hour hand per hour.
- Hence x minute space to be gained by minute hand over hour hand can be calculated as x.(60/55) or x.(12/11)
- The minutes hand to coincide with the hour hand it should trace at first 10 minute spaces;
- And then the hands of the clocks to be opposite to each other minute hand should trace 30 minute spaces i.e. totally it should gain 10+30=40 minute spaces to be opposite to that of hour hand
At what time between 2’O clock and 3’O clock the hands of the clock are opposite to each other.
1. 34(6/11) past 2’Oclock
2. 43(7/11) past 2’Oclock
3. 56 (8/11) past 2’Oclock
4. 64(9/11 past 2’Oclock
At 2’O clock the minute hand will be at 12 as shown
We know that,
- Minute hand gains 55 minute spaces over hour hand in 1 hour
Therefore, Minute hand gain 40 minute spaces over hour hand in 40 × (60/55) = 43(7/11) Hence the hand of the clock will minutes be opposite to each at 43( 7/11 ) past 2’Oclock
Therefore, correct option is 2’
When clock is too fast, too slow
- If a clock or watch indicates 6 hr 10 min when the correct time is 6, it is said that the clock is 10 min too fast
- If it indicates 6. 40 when the correct time is 7, it is said to be 20 min too slow.
Now let us have an example based on this concept.
My watch, which gains uniformly, is 2 minutes. I have to attend a show at noon on Sunday, and is 4 min 48 seconds fast at 2 PM on the following Sunday. Find out when was it correct ?
From Sunday noon to the following Sunday at 2 PM, there are 7 days 2 hours or 170 hours.
The watch gains 2+4 4/5 min in 170 hrs.
Therefore, the watch gains 2 min in 2 (divided by) 6 4/5 (multiply by) 170 hrs i.e., 50 hours.
Now 50 hours = 2 Days 2 Hrs.
Therefore, 2 days 2 hours from Sunday noon = 2 PM on Tuesday.
- What is the angle between the two hands of a clock when the time shown by the clock is 6.30 PM?
Explanation : q = 11/2 m – 30h
= 11/2 *30 – 30 *6
= /165-180/ = 150
- At what time between 3 and 4 o’clock will the minute hand and the hour hand are on the same straight line but facing opposite directions.
(c) 3:39 1/11
(d) 3:49 1/11
Explanation : On straight line means 180 degree angle.
180 = 11/2m – 30h
180 = 11/2 m – 30*3
180 = 11/2m-90
(180+90)2 = 11m
m = 540/11 = 49 1/11
- By how many degrees does the minute hand move in the same time, in which the hour hand move by 280?
Explanation : 28*2 *6 = 3360
- At what time, between 3 o’clock and 4 o’clock, both the hour hand and minute hand coincide each other?
(b) 3:16 4/11
(d) 3:16 7/11
Explanation : Coincide means 00 angle.
0 = 11/2m – 30*3
11m = 90*2 = 180
m = 180/11 = 16 4/11
So time = 3 : 16 4/11
- How many degrees will the minute hand move, in the same time in which the second hand move 4800?
Explanation : Minute hand covers 480/60 = 80