Logic Questions and Answers

Answer: B

Work out the marks of each person. Sunil got 500. Rumana got 50 less than Sunil, so 450. Seema got 20 more than Rumana, so 470. Pooja got 20 less than Seema, so 450.

\[ \text{Rumana} = 450,\quad \text{Pooja} = 450 \]

So Rumana and Pooja got exactly the same marks. Pooja and Seema differ by 20, Seema and Rumana differ by 20, and Rumana and Sunil differ by 50. The answer is Rumana and Pooja, option B.

Answer: C

Ram is 5 feet tall. Mohan is 2 feet taller than Ram, so Mohan is 7 feet. Sohan is 1 foot taller than Ram, which is the sentence the question repeats, so Sohan is 6 feet. Comparing the three heights, Mohan at 7 feet is taller than Sohan at 6 feet and Ram at 5 feet. So Mohan is the tallest. Sohan is only taller than Ram, and Ram is the shortest. The heights can be fixed from the data, so the option that says the tallest cannot be determined is wrong. The answer is Mohan, option C.

Answer: C

Neither reason explains the statement. Reason I says a fly-over was built in city X in the same year, which is a different city and gives no cause for the building in city A. Reason II concerns a promise in the 2019 election manifesto, which comes after the 2018 construction and so cannot have caused it.

Since neither is a possible cause, the answer is 'Neither I nor II is a possible reason'. Choosing only I, only II or both would accept a link that the facts do not support.

Answer: B

The valid inference is R2D2 is the only robot which can repair aeroplanes.

The statements say R2D2 is a robot, it can repair aeroplanes, and no other robot can. Put together, among robots R2D2 alone can repair aeroplanes.

The other options say things the statements never mention. 'Can only repair aeroplanes' and 'can repair only aeroplanes' both claim R2D2 has no other skills or repairs nothing else, but nothing limits what else it can do. 'Only R2D2 is a robot' denies that other robots exist, yet 'no other robot' implies that other robots may well exist.

Answer: C

The inference that follows is Mechanical engineering is a profession well suited for women with masters or higher degrees in mechanical engineering.

The research study found that 99% of women with masters or higher degrees in mechanical engineering were successful in their professions. That directly supports the claim that the profession suits such women, which also contradicts the belief held by 60% of the students polled.

The other options go beyond the paragraph. It shows a mistaken belief about one discipline, not misconceptions about 'various' disciplines. It says nothing about what men with advanced degrees believe, and nothing about how many women pursue such degrees.

Answer: C

The inferences that follow are (ii) and (iv) only.

The proposal says the SITs are to cater to the technological and industrial needs of a developing country. That is (iv) directly, and it is a national purpose of their own, which is (ii).

Statements (i) and (iii) are not supported. Being 'in line with' IITs means modelled on them, not that IIT awards SIT degrees or must be consulted before such institutions are set up. Any option including (i) or (iii) adds a claim the sentence does not make.

Answer: D

The only certain inference is Some Fields medalists have dropped out of college.

June Huh is a Fields medalist who dropped out of college, so at least one Fields medalist dropped out, which is all that “some” claims.

The other statements go beyond the one example. “Every Fields medalist has won an Olympiad medal” is contradicted by Huh himself, who won none. “Everyone who has dropped out of college has won the Fields medal” reverses the relationship and generalises from one person to all dropouts. “All Fields medalists are part-time poets” generalises from one medalist, who in any case was a poet when younger, not necessarily now.

Answer: D

Correct answer: 3, 5, 1, 4, 2

The sequence follows the natural order of cause and effect. Study comes first, then the exam that tests it, then the job the qualification obtains, then the income the job brings, and finally the independence the income makes possible. Each step is the precondition of the one after it.

Answer: D

Correct answer: Sonam

David is below Dechen and above Sonam, and Karma is above David. So Dechen and Karma are both above David and Sonam is the only one below him. The ordering is not complete - nothing settles whether Dechen or Karma is higher - but the bottom position is determined, and it is Sonam’s.

Answer: C

Correct answer: If p is true and q is false and r is false, the P1 is true

Conjunction binds more tightly than disjunction, so the formula reads \( [(p \lor \lnot q) \land (q \to r)] \lor (r \lor p) \). With p true, q false and r false: \( p \lor \lnot q \) is true, \( q \to r \) is true because the antecedent is false, so the bracket is true and the whole is true. It is not a tautology, since p false, q true and r false makes every disjunct false.