 Classification - Logical Reasoning
Classification is the process of classifying objects on the basis of their common properties or relationships like shape, size, color, trait, and category.

Type of classification problems:-
1. Choosing the Odd Word Out
2. Choosing the Odd Pair Out
3. Choosing the Odd Letter Out
4. Choosing the Odd Number Out

1. Choosing the Odd Word Out
In this type of problems, four or five options are given and a candidate has to select the odd word which does not correspond with other words i.e. possess similar properties like other words.

This classification can be based on (i) meaning, (ii) rank, (iii) work, (iv) place, (v) priority, (vi) category, (vii) situation, and so on.

E1. Find the odd word
(a) Peso
(b) Shora
(c) Drachma
(d) Baht

Answer: (b) all except Shora are currencies of their respective countries, while Shora is the parliament of Afghanistan.

E2. Find the odd word
(a) Square
(b) Sphere
(c) Cone
(d) Cuboid

Answer: (a) all except square are three-dimensional objects.

E3. Find the odd word
(a) Silver
(b) Alumunium
(c) Iron
(d) Hydrogen

Answer: (d) all except Hydrogen are metals.

2. Choosing the Odd Pair Out

In this type of problems, four or five pairs of words are given. A candidate has to deduce the relationship between these pair of words and pick the odd pair with a different relationship.

E4. Find the odd pair
(a) See : Eyes
(b) Hear : Ears
(c) Smell : Nose
(d) Tounge : Taste

Answer: (d) In all pairs except (d), first is the function of the second.

E5. Find the odd pair
(a) Church : Monument
(b) Car : Bus
(c) Pond : Lake
(d) Pistol : Gun

Answer: (a) In all pairs except (a), both the words belong to the same class.

E6. Find the odd pair
(a) Aphid : Paper
(b) Termite : Wood
(c) Moth : Wool
(d) Locust : Plant

Answer: (a) In all pairs except (a), second is damaged by the first.

3. Choosing the Odd Letter/Group Out
In this type of problems, a candidate has to choose a letter or letter groups which bear no relationship with other letter or letter group given in options.

E7. Find the odd one
(a) BD
(b) CE
(c) FH
(d) NL

Answer: (d) In all except NL, there is one letter gap between two letters.

E8. Find the odd one
(a) PQRS
(b) LMNOP
(c) ABCD
(d) XYZA

Answer: (b) All except LMNOP letter group have four letters.

E9. Find the odd one
(a) ABCE
(b) FGHI
(c) JKLM
(d) NOPQ

Answer: (a) All except ABCE are consecutive letters.

4. Choosing the Odd Number Out
In this type of problems, four or five numbers are given. A candidate has to find the common property among all options and pick the odd one out which do not correspond to that property.

E10. Find the odd one
(a) 64
(b) 256
(c) 676
(d) 575

Answer: (d) All except 575 are squares of a respective number. 64 = 8 * 8; 256 = 16 * 16; and 676 = 26 * 26

E11. Find the odd one
(a) 145
(b) 158
(c) 151
(d) 143

Answer: (b) All except 158 are odd numbers.

E12. Find the odd one
(a) 25
(b) 75
(c) 15
(d) 105

Answer: (a) All except 25 are divisible by 3.