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Science & Technology

923 questions asked in UPSC Prelims.

1997 · Q135Science & TechnologyQuantitative Aptitudedifficult

There are three drawers in a table. One contains two gold coins, another two silver coins, and the third, a silver coin and a gold coin. One of the drawers is pulled out and a coin is taken out. It turns out to be a silver coin. What is the probability of drawing a gold coin, if one of the other two drawers is pulled out next and one of the coins in it is drawn at random?

  1. (a)37.5%
  2. (b)50%
  3. (c)62.5%
  4. (d)75%
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Official answer(b) 50%

1997 · Q138Science & TechnologyQuantitative Aptitudemoderate

The number of students in two sections, A and B, having different heights is shown in the following table: Height (in metres) Number of students with that height in Section A Section B 1.55 3 2 1.60 7 3 1.62 12 14 1.65 15 14 1.68 8 9 1.71 6 5 1.75 3 4 The ratio of the number of students of a particular height in Section A to that in Section B is the maximum for the height of

  1. (a)1.55 m
  2. (b)1.60 m
  3. (c)1.65 m
  4. (d)1.71 m
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Official answer(b) 1.60 m

1997 · Q139Science & TechnologyData Interpretationmoderate

The following table shows the per cent change in the number of sales (in rupees) at different retail stores in a given neighbourhood market in the period 1993 to 1995: Retail Store — Percent Change 1993 to 1994 — 1994 to 1995 Anshu: +10, -10 Borna: -20, +9 Calpo: +5, +12 Dilip: -7, -15 Elegant: +17, -8 If the sales at Anshu store amounted to Rs. 8 lakhs in 1993, then the number of sales (in lakhs of rupees) at that store in 1995 was

  1. (a)7.92
  2. (b)8.00
  3. (c)8.80
  4. (d)9.68
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Official answer(a) 7.92

1997 · Q142Science & TechnologyLogical Reasoning & Puzzlesmoderate

Seven persons P, Q, R, S, T, U and V participate in and finish all the events of a series of swimming races. There are no ties at the finish of any of the events. V always finishes somewhere ahead of P. P always finishes somewhere ahead of Q. Either R finishes first and T finishes last or S finishes first and U or Q finishes last. If in a particular race V finished fifth, then which one of the following would be true?

  1. (a)S finishes first
  2. (b)R finishes second
  3. (c)T finishes third
  4. (d)R finishes fourth
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Official answer(a) S finishes first

1997 · Q143Science & TechnologyLogical Reasoning & Puzzlesmoderate

Consider the following: I. Saxena, David, Jain and Kumar were District Collectors at places P, Q, R and S respectively in 1970. II. In 1972 they were transferred. Saxena and Jain interchanged places. Kumar and David also interchanged places. III. One year later in 1973 they were again transferred such that David and Jain interchanged places and Saxena and Kumar were also interchanged. What should be the next round of transfers so that all the four persons could have been posted at all the four places?

  1. (a)Interchange Saxena and David as well as Jain and Kumar
  2. (b)Interchange Saxena and Kumar as well as David and Jain
  3. (c)Interchange David and Kumar as well as Saxena and Jain
  4. (d)It is not possible for all the four persons to have been posted at all the four places
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Official answer(a) Interchange Saxena and David as well as Jain and Kumar

1997 · Q146Science & TechnologyLogical Reasoning & Puzzleseasy

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? Choose the correct answer from the codes given below:

  1. (a)I and IV
  2. (b)I and III
  3. (c)II and III
  4. (d)III and IV
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Official answer(a) I and IV