Ranking & Order Test for the Assam Police Constable (AB & UB) Exam
Ranking and Order Test is a reasoning topic of the SLPRB Assam Police Constable (AB & UB) examination in which the position of a person or a thing in a row or a list is described and the candidate must find the total number or the missing position. The questions need no general knowledge and only a little arithmetic, and the whole topic rests on two or three simple formulas. A candidate who writes down the given positions before calculating almost never makes a mistake. This page explains the formulas, the worked examples, the shortcuts and the traps that cost marks. The material follows the standard reasoning reference books used for Assam recruitment examinations and is reviewed before it is published.
What the Topic Means
In this topic a row of persons or a list of items is given, and the position of one of them is described either from the left end or the right end, or from the top or the bottom. Using these positions the candidate must find the total number in the row, the position of another person, or the number of persons between two of them. The two directions of counting, from the two ends, are the heart of the topic.
The Standard Formulas
- Total number in a row equals the rank from the left plus the rank from the right minus one.
- So the rank from the right equals the total minus the rank from the left plus one.
- The number of persons between two persons equals the total minus the sum of their ranks from the same end, minus one.
- If two persons swap places and the change in the rank of one is known, the change gives the number of persons between them.
- When a person is counted from both ends, the person is counted twice, and that is why one is subtracted.
A Step by Step Method
- Draw a small line and mark the two ends, left and right or top and bottom.
- Write the given ranks on the line for the persons mentioned.
- Decide what is asked: the total, a rank, or the number between two persons.
- Apply the formula that matches, and check the answer by counting on the line.
- If the question gives overlapping positions, use the between rule carefully.
Worked Examples
Example one: in a row, Ram is eleventh from the left and fifteenth from the right. The total is 11 plus 15 minus 1, that is 25. Example two: in a class of 40 students, Sita is twelfth from the top. Her rank from the bottom is 40 minus 12 plus 1, that is 29. Example three: in a row of 30 persons, A is tenth from the left and B is fifteenth from the right. The number of persons between them is 30 minus the sum of 10 and 15, minus 1, which is 4. Example four: if two friends exchange places and one moves two places, then two persons were standing between them.
How This Topic Appears in the Examination
The topic usually appears as two to four objective questions of one mark each. The common forms are to find the total number in a row, to find the rank of a person from the other end, to find the number of persons between two persons, and to find the position after a swap or an insertion. The questions are quick because they use one formula each.
Shortcuts and Speed Methods
- Remember that the total is the sum of the two ranks minus one.
- Write the line and mark the ends; a diagram prevents the common errors.
- For the number between two persons, subtract one after removing their positions.
- In swap questions, the number of places moved equals the number of persons crossed.
- Always check the answer by counting on the line once.
Common Mistakes to Avoid
- Forgetting to subtract one, which gives an answer that is too large.
- Adding the ranks from opposite ends without the minus one correction.
- Confusing the rank from the top with the rank from the bottom.
- Counting the two given persons themselves when the question asks for the number between them.
- Applying the total formula when the question actually asks for a rank.
Preparation Plan
- Learn the three main formulas by heart.
- Practise twenty ranking questions a day with a small diagram each time.
- Solve swap and insertion questions separately.
- Check every answer by counting on the line.
- Revise the formulas once a week.
More Practice Questions
- In a row of 20, Ali is ninth from the left, so he is twelfth from the right.
- If a boy is seventh from the top and ninth from the bottom, the class has 15 students.
- In a row of 25, A is fifth from the left and B is eighth from the right, so 12 persons stand between them.
- If a girl is fifth from the left and the total is 18, she is fourteenth from the right.
- If two persons exchange places and one moves three places, three persons were between them.
Quick Revision Checklist
- Total equals left rank plus right rank minus one.
- Right rank equals total minus left rank plus one.
- Persons between equals total minus the sum of the two ranks minus one.
- In swaps, the places moved equal the persons crossed.
- Always draw the line and check by counting.
Frequently Asked Questions
What is the ranking and order test?
It is a reasoning topic in which the position of a person in a row is given from one or both ends, and the candidate must find the total number, a missing rank, or the number of persons between two persons.
What is the main formula in ranking?
The total number in a row equals the rank from the left plus the rank from the right minus one, because the person mentioned is counted from both ends and so is counted twice.
How do I find the number of persons between two persons?
Subtract the sum of their ranks from the same end from the total, and then subtract one more, taking care not to count the two given persons themselves.
Why must I draw a line?
A small line with the ends marked shows the positions clearly and prevents the common errors of adding the wrong ranks or forgetting the minus one correction.
Is ranking scoring in Assam Police?
Yes. Each question uses one simple formula and can be solved in a few seconds, so it is a good place to gain sure marks in the reasoning paper.