Ranking shortcut tricks


     Below are a few tricks that will help candidates to solve the Ordering and Ranking questions in the exam with ease. Before that candidates must keep in mind a few things before applying these tricks.

Note:

  • Read the statement line by line and apply the cases as explained below.
  • Position can be from either sides of row and rank is always from top or bottom of the row

Now, let's discuss each different case in Rank and Order.

(1). Find out total no. of persons in a line

  • In this question, the below formula is used. Total no of persons= Left position in the line + Right position in the line-1.
  • For Example: A is 25th from the left and 32nd from the right, find out the total no of persons in the line.
  • Total no of persons = Left position in the line + Right position in the line-1. Total no of persons = 25 + 32 -1 = 56

(2). Find the total no of persons if there is a given a difference

  • Total no of persons = person's position from the given side or from the top or bottom + given difference
  • For Example: A's position from the top is 17th and the persons behind A are 7. Find out total no of persons in a raw.
  • Total no of persons = person's position from the given side or from the top or bottom + given difference. Total no of persons = 17 + 7 = 24
(3). When total no persons and position of two different persons given from the opposite. Find out no of persons between this two persons. 

  1. If Total no of persons> total of position of both opposite persons
  • Formula: No of persons between two person's position = Total no of persons - total of both persons of opposite position
  • For example: There are 58 persons in a row, in which A is 11th from the left and B is 22nd from the right side of the row. Find out no of people between A and B.
  • No of persons between two person's position = Total no of persons - total of both persons of opposite position No of persons between two person's position =58 - (11+22)
                                                          =58-33 
                                                          =25

 2. If Total no of persons < total of position of both opposite persons

  • Formula: No of persons between two person's position = Total of both persons of opposite position - total of all persons - 2
  • For example: There are 50 persons in a row, in which A is 24th from the left and B is 30nd from the right side of the row. Find out no of people between A and B.
  • No of persons between two person's position =Total of both persons of opposite position - total of all persons - 2
  • No of persons between two person's position = (24+30) - 58                                                        =54-50-2                                                                  =2 
 (4). If persons interchange their positions in a row and the interchange position of one person given. 
 1. Total no of persons in a row = person position before change + person position after change - 1
  • For Example: In a row A is 11st from the left and B is 18th from the right, after interchanging their positions A becomes 29th from the left. Find the total no of persons in a row.
  • Formula: Total no of persons in a row = person position before change + person position after the change - 1
  • Total no of persons in a row = 11 + 29 - 1
                                                      = 39
 2. No of persons between A and B = person position after change - person position before the change - 1
  • Total no of persons in a row = 29 - 11 - 1
                                         = 17
 3. New position of the second person after interchange = Position of the second person from right side before interchanging + (Position of the first person from left side after interchanging – Position of A from left side before interchanging)
  • New position of the second person after interchange = 22+ (29-11)
                       = 18 + 18
                       = 36


Time Shortcut tricks


Introduction

  • A Clock is a circular device provided with three hands viz. an hour hand, minute and second hand. The study of the clock is known as “horology”.

Structure of a Clock

  • A clock is composed of 360 degrees and divided into 12 equal divisions. The angle between the consecutive divisions is obtained by dividing the total angle of clock 360° by the number of divisions i.e. 12.
  • The angle between any two consecutive divisions = (360°)/12= 30°
  • Angular value of a minute = (30°)/5= 6°

Speed of the hands

  • A clock has three hooks and all three move at different rates. The speed of moving object depends on the distance travelled and the time taken to cover a specific range.
  • The speed is calculated by:  Speed = Distance/(Time taken)
  • The speed of a minute hand:
  • A minute hand travels 360° in one hour. i.e. it travels through all the 12 divisions around the clock every hour. (1 hour = 60 minutes).  Speed of a minute hand = (360°)/(60 minutes).  Speed of a minute hand = 6° per minute.
  • The speed of an hour hand:
  •  An hour hand travels 30° in an hour. i.e. it covers a distance of 5 minutes (the gap between consecutive divisions) in 60 minutes. Speed of an hour hand = (30°)/(60 minutes). Speed of an hour hand =1/2 ° per minute.

Frequency of coincidence and collision of hands of a clock
  • How many times in a day do the minute and hour hands of a clock coincide (Angle between them is zero) with each other? --- In 12 hours there will be 11 coincidences. 
  • How many times in a day do the minute and hour hands of clock form a 180° straight line in a day? --- The hands of a clock make 180° straight lines 11 times in 12 hours and hence generalising it for 24 hours, the hands make 22 consecutive lines of 180° in 24 hours.
  • To get a mirror image to consider 12 O'clock, which can write 11.60 and subtract the given time from 11.60 to the answer. 
  • To get the water image to consider 6.30 (18.30), which can write as 17.90, and subtract the given time to get the answer.