UPSC Prelims 2021 · CSAT
Question 68: Basic Numeracy
A cubical vessel of side 1 m is filled completely with water. How many millilitres of water is contained in it (neglect thickness of the vessel) ?
AnswerUPSC’s answer is (d).
1 m = 100 cm, so the volume is 100 × 100 × 100 = 1,000,000 cm³. One cubic centimetre holds one millilitre, so the vessel holds 1,000,000 mL. Equivalently, 1 m³ = 1000 litres and 1 litre = 1000 mL. Remember: 1 m³ = 1000 L = 10^6 mL, a conversion worth memorising for the exam.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) 1000 is the number of litres, not millilitres.
- (b) 10,000 is not a standard conversion of 1 m³.
- (c) 100,000 mL would be 100 litres; the vessel holds 1000 litres.
- (d) Right: 1 m³ = 10^6 cm³ = 1,000,000 mL.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.