UPSC Prelims 2019 CSAT Paper II · Q20 of 79 Basic Numeracy easy

In a conference, out of a total 100 participants, 70 are Indians. If 60 of the total participants are vegetarian, then which of the following statements is/are correct ? 1. At least 30 Indian participants are vegetarian. 2. At least 10 Indian participants are non-vegetarian. Select the correct answer using the codes given below :

  1. (a) 1 only
  2. (b) 2 only
  3. (c) Both 1 and 2 ✓ UPSC's answer
  4. (d) Neither 1 nor 2

Why the answer is (c)

• Total participants = 100, Indians = 70, Non-Indians = 30.

• Total vegetarians = 60, Total non-vegetarians = 40.

• To find the minimum number of Indian vegetarians, assume the maximum number of Non-Indian vegetarians. Since there are only 30 Non-Indians, at most 30 can be vegetarians.

• Therefore, minimum Indian vegetarians = Total vegetarians (60) - Max Non-Indian vegetarians (30) = 30. Statement 1 is correct.

• To find the minimum number of Indian non-vegetarians, assume the maximum number of Non-Indian non-vegetarians. Since there are only 30 Non-Indians, at most 30 can be non-vegetarians.

• Therefore, minimum Indian non-vegetarians = Total non-vegetarians (40) - Max Non-Indian non-vegetarians (30) = 10. Statement 2 is correct.

• Since both statements are correct, option (c) is the answer.

Why the other options are wrong

(a) 1 only
Statement 2 is also correct, so selecting only statement 1 is incomplete.
(b) 2 only
Statement 1 is also correct, so selecting only statement 2 is incomplete.
(d) Neither 1 nor 2
Both statements are mathematically proven to be correct, so neither being correct is false.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2019, held on 2 June 2019. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

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