Figure Series for the Assam Police Constable (AB & UB) Exam
Figure Series, also called series completion, is a non-verbal reasoning topic of the SLPRB Assam Police Constable (AB & UB) examination in which a sequence of figures is shown and the candidate must find the figure that comes next or the missing figure in the middle. The topic is included to test observation, the ability to detect a pattern and the speed of applying it. No general knowledge and no language skill are needed; the whole question is solved by watching how the figure changes from one step to the next. A candidate who notes the changes of shape, size, number, position, rotation and shading almost never makes a mistake. This page explains the types of series, the patterns of change, 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
A figure series is a row of figures in which each figure is related to the one before it by one or more fixed changes. The figures may be geometrical shapes, letters, small designs, lines, dots or a mixture of these. The candidate is asked either to choose the next figure that continues the rule or to fill a blank place inside the series. The rule that connects the figures is never random; it is a repetition of a simple change such as turning the figure, adding a line, increasing a number, moving a dot or reversing the shading. Once the rule is found the answer follows at once.
How a Figure Series Is Built
Most series are built in one of four ways. In the first type the same change happens at every step, for example the figure rotates clockwise by one quarter turn each time. In the second type two or more changes happen together, for example the outer shape loses one side while the inner dot moves to the next corner. In the third type the series alternates, so two different rules act on the odd and the even places. In the fourth type the changes grow, for example the figure turns thirty degrees, then sixty, then ninety. Recognising which type is being used is the first and most important step.
The Common Patterns of Change
- Rotation of the whole figure by a fixed angle, clockwise or anticlockwise.
- Addition or removal of a line, a side, a dot or a curve at each step.
- Increase or decrease in the number of a repeated element.
- Movement of a small element from one position to the next, such as a dot moving corner to corner.
- Change of shading, filling, colour or the interchange of black and white.
- Mirroring, inversion or turning the figure upside down.
- Change of size, the figure growing larger or smaller in a fixed ratio.
- A combination of two of the above, which is the most common in the examination.
A Step by Step Method
- Look at the first two figures and note exactly what has changed.
- Check the next pair and confirm whether the same change has taken place.
- Write down the change in one short sentence, such as the figure turns ninety degrees to the right.
- Apply that change to the last given figure to get the answer, or fill the blank by counting backwards.
- Match the answer with the options and reject any option that breaks the confirmed rule.
- If the series alternates or grows, find the two rules separately before answering.
Worked Examples
Example one: a triangle points upward, then to the right, then downward, then to the left. The figure is turning ninety degrees clockwise, so the next triangle points upward again. Example two: a square has one dot, then two dots, then three dots, then four dots. The number of dots is increasing by one, so the next square has five dots. Example three: a circle is shaded, then unshaded, then shaded, then unshaded. The shading alternates, so the next circle is shaded. Example four: a small line inside a box moves to the right by one position each time, so after it reaches the last position it returns to the first. Example five: the outer figure changes from a triangle to a square to a pentagon, so the number of sides increases by one and the next figure is a hexagon.
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 next figure in the series, to find the missing figure in the middle, to find the wrong figure that does not follow the rule, and to complete a series of letters or symbols. Each question carries four or five options which are close to one another, so the candidate must be sure of the rule before choosing.
Shortcuts and Speed Methods
- Check the simplest changes first, namely rotation, counting and position, before looking at shading or size.
- Compare only two neighbouring figures at a time; the whole row need not be studied at once.
- Say the rule aloud in a few words; if it cannot be said simply, the rule is probably wrong.
- For alternating series, solve the odd and the even places as two separate short series.
- Reject options that clearly break the rule instead of checking every option in full.
Common Mistakes to Avoid
- Guessing the answer from a single change without confirming it on the next pair.
- Choosing the change that seems attractive but is not repeated in the series.
- Ignoring a second change that happens along with the main change.
- Forgetting the direction of rotation and turning the figure the wrong way.
- Mixing up the odd and the even positions in an alternating series.
Preparation Plan
- Learn the list of common changes by heart.
- Practise twenty series questions a day, writing the rule for each in one line.
- Separate the practice of rotation series, counting series and alternating series.
- Time yourself so that each question takes less than a minute.
- Revise the common changes once a week until they are recognised at a glance.
More Practice Questions
- A figure turns forty-five degrees clockwise each time; after four steps it has turned half a circle.
- A pattern of one, four, nine and sixteen dots is the series of squares of numbers, so the next is twenty-five.
- If a shape loses one side each time, a hexagon becomes a pentagon, then a square, then a triangle.
- In an alternating series of shaded and unshaded circles, every odd place is shaded.
- A dot moving one corner forward in a square returns to its first corner after five steps.
Quick Revision Checklist
- Find the change between two neighbouring figures first.
- Confirm the change on the next pair before answering.
- Look for rotation, counting, position, shading, size and mirroring.
- For alternating series, split the series into odd and even places.
- State the rule in one short sentence and then choose the option.
Frequently Asked Questions
What is a figure series?
It is a non-verbal reasoning topic in which a row of figures changes according to a fixed rule, and the candidate must find the next figure or a missing figure in the series.
What changes should I look for?
Look for rotation, addition or removal of lines, change in the number of an element, movement of a small part, change of shading or size, and mirroring, and also for a combination of these.
How do I solve an alternating series?
Treat the odd places and the even places as two separate short series, find the rule in each, and then decide which rule applies to the missing place.
How much time should one question take?
A well-practised candidate should finish one figure series question in under a minute, because the rule once seen is applied in a single step.
Is figure series scoring in Assam Police?
Yes. Each question uses one observable rule and can be solved quickly, so it is a reliable place to gain marks in the reasoning paper.