Logical reasoning MCQ with Answers

20 questionswith explanationsfor RAS, Patwari, VDO and other Rajasthan exams

Questions

Q1

Find the next number in the series: 2, 6, 12, 20, 30, ?

(1)40
(2)36
(3)44
(4)42✓ Correct answer

Answer: (4) 42

Explanation

Differences are 4, 6, 8, 10, so next difference is 12: 30 + 12 = 42.

Q2

Find the next number in the series: 3, 7, 15, 31, 63, ?

(1)127✓ Correct answer
(2)126
(3)125
(4)129

Answer: (1) 127

Explanation

Each term = previous × 2 + 1: 63 × 2 + 1 = 127.

Q3

If CAT is coded as DBU, how will DOG be coded in the same code?

(1)EPI
(2)CNF
(3)EPH✓ Correct answer
(4)FQI

Answer: (3) EPH

Explanation

Each letter is moved one place forward: D→E, O→P, G→H.

Q4

A man walks 3 km north, then turns right and walks 4 km. How far is he from his starting point?

(1)7 km
(2)5 km✓ Correct answer
(3)1 km
(4)6 km

Answer: (2) 5 km

Explanation

The paths are at right angles: distance = √(3² + 4²) = 5 km.

Q5

Find the next term: A, C, F, J, O, ?

(1)U✓ Correct answer
(2)T
(3)V
(4)S

Answer: (1) U

Explanation

Positions 1, 3, 6, 10, 15 increase by 2, 3, 4, 5; next +6 gives 21 = U.

Q6

If ROSE is written as TQUG in a certain code, how is MILK written in that code?

(1)NJML
(2)OKNM✓ Correct answer
(3)OKMN
(4)PLNM

Answer: (2) OKNM

Explanation

Each letter is moved two places forward: M→O, I→K, L→N, K→M.

Q7

Pointing to a boy, Rita said, 'He is the son of my father's only son.' How is the boy related to Rita?

(1)Son
(2)Brother
(3)Nephew✓ Correct answer
(4)Cousin

Answer: (3) Nephew

Explanation

Rita's father's only son is Rita's brother; his son is Rita's nephew.

Q8

A is the brother of B. C is the mother of A. D is the father of C. How is D related to B?

(1)Father
(2)Maternal uncle
(3)Paternal uncle
(4)Maternal grandfather✓ Correct answer

Answer: (4) Maternal grandfather

Explanation

C is the mother of A and B; D is C's father, so D is B's maternal grandfather.

Q9

A person is facing north. He turns 90° clockwise, then 180°, and then 90° anticlockwise. Which direction is he facing now?

(1)North
(2)South✓ Correct answer
(3)East
(4)West

Answer: (2) South

Explanation

North → 90° clockwise = East → 180° = West → 90° anticlockwise = South.

Q10

Statements: All roses are flowers. Some flowers are red. Conclusions: I. Some roses are red. II. Some flowers are roses. Which conclusion(s) follow?

(1)Only conclusion I follows
(2)Both I and II follow
(3)Neither I nor II follows
(4)Only conclusion II follows✓ Correct answer

Answer: (4) Only conclusion II follows

Explanation

'All roses are flowers' converts to 'Some flowers are roses' (II follows). The red flowers may not include any rose, so I does not follow.

Q11

Statements: All cats are dogs. No dog is a rat. Conclusions: I. No cat is a rat. II. Some dogs are cats. Which conclusion(s) follow?

(1)Both I and II follow✓ Correct answer
(2)Only conclusion I follows
(3)Only conclusion II follows
(4)Neither I nor II follows

Answer: (1) Both I and II follow

Explanation

All cats lie inside dogs and no dog is a rat, so no cat is a rat (I). 'All cats are dogs' converts to 'Some dogs are cats' (II).

Q12

Ram walks 10 m south, turns left and walks 20 m, turns left and walks 10 m, then turns right and walks 5 m. How far and in which direction is he from his starting point?

(1)25 m west
(2)15 m east
(3)25 m east✓ Correct answer
(4)35 m east

Answer: (3) 25 m east

Explanation

South 10, then east 20, then north 10 (back on the starting line), then east 5: total 25 m east.

Q13

Statements: All teachers are graduates. All graduates are voters. Conclusions: I. All teachers are voters. II. Some voters are teachers. Which conclusion(s) follow?

(1)Only conclusion I follows
(2)Only conclusion II follows
(3)Both I and II follow✓ Correct answer
(4)Neither I nor II follows

Answer: (3) Both I and II follow

Explanation

Teachers ⊂ graduates ⊂ voters, so all teachers are voters (I), and its converse 'some voters are teachers' (II) also holds.

Q14

Statements: Some pens are books. No book is a bag. Conclusions: I. Some pens are not bags. II. No pen is a bag. Which conclusion(s) follow?

(1)Only conclusion I follows✓ Correct answer
(2)Only conclusion II follows
(3)Both I and II follow
(4)Neither I nor II follows

Answer: (1) Only conclusion I follows

Explanation

The pens that are books cannot be bags, so I follows; other pens may still be bags, so II does not follow.

Q15

Statements: All chairs are tables. Some tables are boxes. Conclusions: I. Some chairs are boxes. II. Some boxes are tables. Which conclusion(s) follow?

(1)Only conclusion I follows
(2)Only conclusion II follows✓ Correct answer
(3)Both I and II follow
(4)Neither I nor II follows

Answer: (2) Only conclusion II follows

Explanation

II is the converse of 'Some tables are boxes', so it follows; the tables that are boxes need not be chairs, so I does not follow.

Q16

Statements: Some kites are birds. Some birds are planes. Conclusions: I. Some kites are planes. II. All planes are kites. Which conclusion(s) follow?

(1)Only conclusion I follows
(2)Only conclusion II follows
(3)Both I and II follow
(4)Neither I nor II follows✓ Correct answer

Answer: (4) Neither I nor II follows

Explanation

Two 'some' premises give no definite link between kites and planes, so neither conclusion follows.

Q17

Statements: All mangoes are fruits. No fruit is a vegetable. Some vegetables are green. Conclusions: I. No mango is a vegetable. II. Some green things are not fruits. Which conclusion(s) follow?

(1)Only conclusion I follows
(2)Only conclusion II follows
(3)Both I and II follow✓ Correct answer
(4)Neither I nor II follows

Answer: (3) Both I and II follow

Explanation

Mangoes lie inside fruits, which share nothing with vegetables, so I follows; the green vegetables are green things that are not fruits, so II follows.

Q18

Statement: "Use Brand X water purifier and keep your family safe from water-borne diseases." — an advertisement. Assumptions: I. People want to protect their families from water-borne diseases. II. Purifying drinking water can help prevent water-borne diseases. Which assumption(s) is/are implicit in the statement?

(1)Only assumption I is implicit
(2)Only assumption II is implicit
(3)Both I and II are implicit✓ Correct answer
(4)Neither I nor II is implicit

Answer: (3) Both I and II are implicit

Explanation

The advertiser assumes people care about this protection (I) and that purification can prevent such diseases (II); otherwise the appeal would be pointless.

Q19

Statement: The State Government has decided to give free bicycles to girl students of Class 9 who live more than 2 km away from their school. Assumptions: I. Distance from school makes it difficult for some girls to attend school regularly. II. All girl students of Class 9 live more than 2 km away from their school. Which assumption(s) is/are implicit in the statement?

(1)Only assumption I is implicit✓ Correct answer
(2)Only assumption II is implicit
(3)Both I and II are implicit
(4)Neither I nor II is implicit

Answer: (1) Only assumption I is implicit

Explanation

The scheme targets distance as a hurdle, so I is implicit; the 2 km condition itself shows not all girls live that far, so II is not implicit.

Q20

Statement: "If you want a good job, you must be proficient in computers," a career counsellor told the students. Assumptions: I. All the students are already proficient in computers. II. Employers offering good jobs value computer proficiency. Which assumption(s) is/are implicit in the statement?

(1)Only assumption I is implicit
(2)Only assumption II is implicit✓ Correct answer
(3)Both I and II are implicit
(4)Neither I nor II is implicit

Answer: (2) Only assumption II is implicit

Explanation

The advice rests on employers valuing computer skills (II); if all students were already proficient the advice would be needless, so I is not implicit.