# TEST-REASONING ABILITY NOTES

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A sequence of several terms is known as series. Each unit of a sequence or series is called a term or an element. All terms in a series follow a certain pattern throughout the sequence. Each term in the series is important because there exists a certain relationship between two consecutive terms. Several types of questions are asked on series in competitive examinations. There are two types of series. The questions based on the English Alphabet series are somewhat easy because one can remember the position of each alphabet easily. e.g. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
(i) Find the eighteenth letter in the above alphabet series.
The 18th letter counting from the left end is ‘R’.
(ii) Find the tenth letter from the right.
When we count from the right to the left, the tenth letter is ‘Q’.
This is an example of simple series and questions on this are relatively simple.
Mixed Series: It consists of letters, numbers and symbols Unlike the English alphabet series, the number of elements in mixed series is not fixed. It can have any number of elements like 24, 25, 26, 28 or even more. Questions on series judge how quickly one can identify the relationship between the given elements. To solve questions on this, a lot of practice is required because there are hardly any shortcuts to solve them. Questions on series can be classified into two types.
(1) Questions on series consisting of letters and numbers.
T G L 8 A V E R 6 M I 3 U Z D S W 7 5 F J B Y Q 2 1 K
e.g. If the question is to find which letter/number is fourth to the left of the 16th letter/number from your left First and the 16th letter/number from the left, which, in this case, is ‘S’ and the fourth letter/ number to the left of ‘S’is ‘3’. In short, you are asked to find out 16 – 4 = 12th letter number from left.
(2) Questions on series consisting of letters, numbers and symbols.
The series is made more complicated by including letters, numbers and symbols in it.
e.g. Study the following series of letters, numbers and
symbols.

= N R < 2 A F 3 @ L M Z P > Q 5 4 R T J 6 K L # \$ 9 8 * 3
Different types of questions based on this series can be asked, e.g. If the first thirteen elements are written in the reverse order, which letter/number/symbol will be the sixth to the left of the twelfth letter/number/symbol from your right?
Solution: When the first thirteen elements are written in the reverse order, the sequence is as follows:

P Z ML @ 3 F A 2 < R N = > Q 5 4 R T J 6 K L # \$ 9 8 * 3
The twelfth letter from the left is ‘N’ and the sixth element to the left of ‘N’ is 3.
Remember the important points given below when solving questions on series.
(1) Quickly count the total number of terms in the given series.
(2) Locate the middle term if any.
(3) Write down the total number of letters, numbers and symbols respectively.