CSAT › Logical Reasoning – UPSC Prelims PYQs

Examine the following statements regarding a set of balls: I. All balls are black. II. All balls are white. III. Only some balls are black. IV. No balls are black. Assuming that the balls can only be black or white, which two statements given above can both be true, but cannot both be false?

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Consider the figures given below:

(In the given sequence of figures, the figure that would logically appear at Sl. No. V is) The original figure is not available for this question.

Examine the following statements:

I. George attends Music classes on Monday. II. He attends Mathematics classes on Wednesday. III. His Literature classes are not on Friday. IV. He attends History classes on the day following the day of his Mathematics classes. V. On Tuesday, he attends his Sports classes. If he attends just one subject in a day and his Sunday is free, then he is also free on

Two important characteristics of a hypothesis are that it should be testable and that it should be stated in a manner that it can be refuted.

Which one of the following hypotheses fulfils these characteristics?

Six roads lead to a country. They may be indicated by letters X, Y, Z and digits 1, 2, 3. When there is storm, Y is blocked. When there are floods X, 1 and 2 will be affected. When road 1 is blocked, Z also is blocked. At a time when there are floods and a storm also blows, which road(s) can be used?

Which one of the following Venn diagrams correctly illustrates the relationship among the classes: Carrot, Food, Vegetable?

In the given figure, the triangle represents girls, the square represents sportspersons and the circle represents coaches. The portion in the figure which represents girls who are sportspersons but not coaches is the one labelled

The next pair of letters in the series AZ, CX, FU, ...... is

Mouse is to cat as fly is to

A man starts walking in the north-easterly direction from a particular point. After walking a distance of 500 metres, he turns southward and walks a distance of 400 metres. At the end of this walk he is situated

Examine the following statements: I. All children are inquisitive. II. Some children are inquisitive. III. No children are inquisitive. IV. Some children are not inquisitive.

Among these statements, the two statements which cannot both be true simultaneously but can both be false would be

Examine the following statements: I watch TV only if I am bored.

I am never bored when I have my brother’s company. Whenever I go to the theatre, I take my brother along.

Which one of the following conclusions is valid in the context of the above statements?

In the given diagram, circle A represents teachers who can teach Physics, circle B represents teachers who can teach Chemistry and circle C represents those who can teach Mathematics. Among the regions marked p, q, r, s, t, u and v, the one which represents teachers who can teach Physics and Mathematics but not Chemistry, is

Seven men, A, B, C, D, E, F and G are standing in a queue in that order. Each one is wearing a cap of a different colour like violet, indigo, blue, green, yellow, orange and red. D is able to see in front of him green and blue but not violet. E can see violet and yellow, but not red. G can see caps of all colours other than orange. If E is wearing an indigo-coloured cap, then the colour of the cap worn by F is

Which of the following can be inferred from the statement that “Either John is stupid or John is lazy”? I. John is lazy / therefore, John is not stupid. II. John is not lazy / therefore, John is stupid. III. John is not stupid / therefore, John is lazy. IV. John is stupid / therefore, John is not lazy.

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