Symbols, Notations & Sequences

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Theory

There are two types of questions asked from this topic

1) A string of numbers is separated by letters where each letter represents a mathematical operator. These questions come under symbols and notations

2) A string of characters is given and we have to count cases or perform some string manipulation on the given sequence

The second type of questions are far more common.

Theory

Symbols and Notations are the type of questions where alphabets are presented with some inequality symbols and mathematical operators. Based on the given examples, we are expected to apply the same logic to the operations given in the question.

Theory

In this topic, a series of letters, numbers and special characters is given and we are asked questions about the series. Commonly asked questions are how many letters are followed by special character or preceded by a number, if vowels are deleted which would be the nth element etc.

Theory

A, E, I, O and U are vowels. There are 5 vowels.
B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, Z are consonants. There are 21 consonants.
Any thing formed by 0-9 are numbers.
!@#$%^&*()_+ etc are special characters.

Tip

If a question is asked about the reverse order, write the reverse down. If a question is asked about eliminating a type of letter/number/character, strike it off from the series.

Tip

Write the series down in groups of 5. It would make counting much easier.

Shortcuts

The nth character to the right of the mth character from the right is the (m-n)th character from the right.
The nth character to the right of the mth character from the left is the (m+n)th character from the left.
The nth character to the left of the mth character from the right is the (m+n)th character from the right.
The nth character to the left of the mth character from the left is the (m-n)th character from the left.

Tip

Try to split the statement given into subparts to identify the bits that are relevant to the questions that follow.

Solved Example

Observe the series given below and answer the questions that follow:

ACBEBCEAABCEABCEEACCABEBBECAACBCEBAE

Are there more consonants or vowels in the given series?
a)consonants
b)vowels
c)same number of vowels and consonants
d)data not sufficient
e)None of the above

Explanation:
There are 18 consonants and 18 vowels. Hence, there are same number of consonants and vowels.

Solved Example

Observe the series given below and answer the questions that follow:

ACBEBCEAABCEABCEEACCABEBBECAACBCEBAE

If all the Cs are eliminated, which is the seventeenth element from the right?
a)A
b)B
c)C
d)E
e)None of the above

Explanation:
If all the Cs are eliminated, the series becomes
ABEBEAABEABEEAABEBBEAABEBAE
We split the series so that we can count easily
ABE BEA ABE ABE EAA BEB BEA ABE BAE
Hence, the 17th letter is B.

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