Logical Sequence of Time


Logical Sequence of Time - Concepts
Class - RRB Technician Grade I Signal Subjects
 
 
Concept Explanation
 

Logical Sequence of Time

Logical Sequence Of Time: Sequence simply implies arrangement of occurrence of events in accordance to the passage of time. That is to say, that which event occurs at what time followed and preceded by which events and at what times and so on so forth. To solve such problems, a base time is convenient in accordance to the conditions specified in the questions. The times of occurrence of all other events are measured in reference to the base time. The key to solving these questions is to use common sense and overall logical reasoning. All this, of course, is better explained by the use of examples which are given below.

Illustration:  A bus for Delhi leaves after every thirty minutes. An enquiry clerk told a passenger that the bus had already left ten minutes ago and the next bus would leave at 9:35 a.m. At what time did the enquiry clerk give this information to the passenger?

A. 9:10 a.m.              B. 8:55 a.m.              C. 9:05 a.m.          D. 9:15 a.m.

Answer: D

Sol.  The next bus will leave at 9:35 a.m. As this is the only concrete time given in the question, let this be the base time. This means that the previous bus had left at 9:05 a.m. But it happened ten minutes before the clerk gave the information to the passenger. Thus, the enquiry clerk gave the information at 9: 15 a.m.

Hence, the correct choice is (4).

Illustration:  At 8 p.m. on Thursday. Kiran's watch was slow by 5 minutes. But at 8 a.m. on Sunday. it was fast by 10 minutes. At what time did it give the right time?

A. 8 p.m. on Saturday              B. 4 p.m. on Friday               C. 12 noon on Saturday             D. 12 a.m. on Friday

Answer: B

Solution: From 8 p.m. on Thursday to 8 a.m. on Sunday, there are 2 complete days and one half day, i.e. 2 X 24 + 12 = 60 hours gap, and the watch gains (5 + 10) 15 minutes. In the time the non defective clock registers a time span of 60 hours,

So 15 minutes are gained in 60 hours

or   1 minute is gained in 60/15 = 4 hours

or   5 minutes are gained in = 4 X 5 = 20 hours

Let the base time be 8pm on Thursday and adding 20 hours we will get 4pm on Friday

Thus, the correct time will be on 4:00 p.m. on Friday. Hence, answer option B is correct.

Ex, 3 Satisfy remembers that his brother's birthday is after fifteenth but before eighteenth of Feburary whereas his sister Kajal remembers that her brother's brithday is after sixteenth but below nineteenth of Feburary. On which day in feburary is Satish's brother's brithday?

(a) 16th                 (b) 17th                   (c) 18th                       (d) 19th               (e) None of these

Sol. Accordinf to Satish, the brother's birthday is on one of the days among 16th and 17th February.

According to kajal, the brother's birthday is on one of the days among 17th and 18th February.

Clearly, Satish's brother's birthday is on the day common to both the above groups, i.e. 17th February.

hence, the answer is (b)

Ex. 4 If the seventh day of a month is three days earlier than Friday,  will it be on the nineteenth day of the month?

(a) Sunday                 (b) Monday                 (c) Wednesday                    (d) Friday

Sol. As, mentioned, the seventh day of the month is three days earluier than Friday, which is tuesday.

So, the fourteenth day is also Tuesday and thus, the nineteenth day is Sunday.

Hence, the answer is (a).

Sample Questions
(More Questions for each concept available in Login)
Question : 1

There are twenty people working in an office . The first group of five work between 8.00 a.m and 2.00 p.m. The second group of ten works between 10.00 a.m. and 4.00 p.m. And the third group of five works between 12 noon and 6.00 p.m. There are three computers in the office which all the employees frequently use. During which of the following hours the computers are likely to be used most?

Right Option : B
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Explanation
Question : 2

An application was received by inward clerk in the afternoon of a week day. Next day he forwarded it to the table of the senior clerk, who was on leave that day. The senior clerk next day evening put up the application to the desk officer. Desk  office studied the application and disposed off the matter on the same a day,i.e.,Friday .which day was the application received by the inward clerk ?

Right Option : C
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Explanation
Question : 3

A bus for Delhi leaves after every thirty minutes. An enquiry clerk told a passenger that the bus had already left five minutes ago and the next bus would leave at 9:35 a.m. At what time did the enquiry clerk give this information to the passenger?

Right Option : A
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Explanation
 
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