Series Alphabet Reasoning: Concepts & Tricks

The reasoning section of almost every competitive examination contains questions on Alphabet Reasoning.In this topic, questions are asked relating to positions of English alphabets. This topic is very important from exam point of view. So you need to memorize the positions of the alphabets so that you can handle each and every question based on this topic. Let us discuss various types of alphabet reasoning:
1. THE ALPHABET: The English alphabet contains 26 letters, as given below:
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
From A to M, the alphabet completes the first 13 letters that is the first half, while the second half starts from 14th letter that is it starts from N and ends at Z.
(First Alphabetical Half) A to M ⇒ 1 to 13
(Second Alphabetical Half) N to Z ⇒ 14 to 26
2. Concept of EJOTY: The positions of alphabets can be remembered with the help of this simple concept, you can easily find out the position of any letter without much effort. But it is advisable that you learn the positions of different letters in the alphabet.
EJOTY
510152025
For example, we are asked to find the 24th letter from the left side of the alphabet. We already know that the 25th letter from the left-hand side is Y, now we need to find letter before Y and that is X. By using this simple method, we can easily find out the position of any letter in the alphabet. Memorizing the positions & sequence of letters is a basic to solve any questions of this type, so you should try to memorize these positions. For this particular reason, you should practice EJOTY. Write down the names of ten of your friends & do as given below:
Let us take an example of name RAVI. With the help of EJOTY, we know that the letter R stands for number 18, A stand for 1, V stands for 22, I stands for 9. Adding all these numbers, we get (18+1+22+9). This is a very good way to remember the positions of all the letters in the alphabet.
3. Positions of letters from Right Hand Side (RHS): Many a times we get questions in the tests that ask us the position of a letter from the right hand side. Although we are in a habit of counting from the left side of the alphabet & not from the right hand side of the alphabet. We are discussing this by taking an example and then we will make a mathematical formula.
Suppose there is a row of 8 persons in which a person is standing 5th from left. Let's find out his/her position from the right side.
IIIIIII1
1st2nd3rd4th5th6th7th8th
You can see that the person who was standing fifth from the left hand side is placed fourth from the right side. Suppose there are ‘n’ persons, the order can be horizontal (from left to right) or vertical (from top to bottom) and if the position of a person is given which is rth from left then his position from right will be (n+1-r). Likewise this concept can also be used if their sitting order is vertical. Sum of positions from left and from right will always be (n+1). As given in the above mentioned example there are 8 persons, position of 5th person from left will be 4th (8+1-5)from right. Sum of both the positions is (4 + 5) = 9. If we are dealing with letters & we are given the position of any letter from either side, we need to add 1 more to the total number of letters & then subtract the position from left side to get its position from the right side.
For instance, let us find the position from right side of a letter, which is the 10th from left side.
ABCDEFGHIJKLMN
1234567891011121314
OPQRSTUVWXYZfrom LHS
151617181920212223242526from RHS
As you can see, the 10th letter from the left hand side of the alphabet is J, which is 17th letter (26+1-10) from the right hand side of the alphabet. We did this operation by adding 1 to the total number of letters (26 + 1 = 27) and then subtracting 10 from it. This same logic is to be applied if we have given an initial right position and we need to find the position from the left side, or we have given initial position from top and we have to calculate position from bottom and vice-versa
4. Finding the central symbol/letter/digit: Many a times the question asks the middle letter/digit in the sequence given e.g. find the middle letter between the 12th letter and the 20th letter from the left hand side of the alphabet.
ABCDEFGHIJKLM
12345678910111213
NOPQRSTUVWXYZ
14151617181920212223242526
You can see that there are 7 letters between these 2 positions i.e. M, N, O, P, Q, R and S. We know that the midpoint of 7 items is the 4th item from either of the sides, whether counted from the right hand side of the alphabet or the left hand side of the alphabet. It comes out to be P, which is the correct answer in this particular case. But so much effort is not needed in solving such questions. In these type of questions, if the two different positions are given from the same side (i.e. either both are from the left hand side of the alphabet or both are from the right hand side of the alphabet), we can simply add up the 2 different positions from the same side, get their simple average and thus, the correct answer. In this particular case, the two positions are 12 and 20 from the left hand side of the alphabet. Adding and then averaging them, we get 16. Recollecting the EJOTY formula that we discussed earlier, we come up with the letter which is 16th from left side (after O) is P. The same process can be applied if we are given a case in which both the positions are counted from the right hand side of the alphabet. Remember, the answer we get will be from the same from both sides. Let’s make this clearer by discussing an illustration.
Consider a scenario in which we have to find the mid-point between the 11th and the 17th letter from the right hand side of the alphabet. Adding the two positions, we get total as 28. The average of these two numbers is therefore 14. So, the mid-point is 14th from the right hand side of the alphabet (the same as the sides given in the question). Now we will convert this position into a position from the left hand side of the alphabet. Applying the logic which we had applied earlier, we will subtract 14 from 27 and get the answer- 13th from the left hand side of the alphabet, which is M. You can verify this answer by looking up the above alphabet.
5. Fill in the blank Series
These types of series consist of small letters which follow a specific pattern or series. Some spaces are left blank in between the series given. We have to fill in the blanks from given options to make a pattern. This can be clearly explained by this illustration:
Illustration: pq_ _ qpp_ _ pq _
1. ppppp
2. ppqpp
3. ppqpq
4. qppqq
Sol: In order to solve these kinds of series, we should fill the given blanks by taking each option one by one & see where it forms a logical pattern. When you try to fill the first option, it becomes pqppqpppppqp. It does not result into any particular logical pattern. If you fill the second option you get pqp/pqp/pqp/pqp. It has been separated by the symbol “/” for your better understanding. Now, this becomes a pattern of writing pqp again & continously. So, the second option becomes the correct answer to this given question.