UPSC Prelims 2016 · CSAT
Question 28: Basic Numeracy
30 g of sugar was mixed in 180 ml water in a vessel A, 40 g of sugar was mixed in 280 ml of water in vessel B and 20 g of sugar was mixed in 100 ml of water in vessel C. The solution in vessel B is :
AnswerUPSC’s answer is (d).
Compare sugar to water. A = 30/180 = 1/6 = 0.167, B = 40/280 = 1/7 = 0.143, C = 20/100 = 1/5 = 0.2. B has the least sugar per unit of water, so B is less sweet than C, and also less sweet than A. Comparing sugar to the whole solution (A 0.143, B 0.125, C 0.167) gives the same order. So B is less sweet than C.
Why each option is right or wrong
- (a) B has less sugar per unit water than C (1/7 against 1/5).
- (b) B (1/7) is less sweet than A (1/6), not more.
- (c) The ratios 1/7 and 1/5 differ.
- (d) Right: 1/7 is less than 1/5.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2016, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.