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WBCS Main Examination 2023 — Paper IV: General Studies II · Question 189 of 200

Q189
General ScienceChemistry
What is the amount of methane in cow dung?
  1. a.30%
  2. b.40%
  3. c.50%
  4. d.60%

No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: question is imprecise — dung biogas is about 50–75% methane, so (C) 50% and (D) 60% are both defensible.

Cow dung itself has no fixed methane content; it is the biogas produced from it that is mostly methane, quoted variously as 50–75% (commonly about 55–65%). With more than one option defensible, the Commission awarded the mark to all candidates.

Q188 Whole paperQ190