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 :

(a) sweeter than that in C
(b) sweeter than that in A
(c) as sweet as that in C
(d) less sweet than that in C ✓ UPSC's answer

Why the answer is (d)

• Calculate the sugar concentration in vessel A: 30 g / 180 ml = 1/6 g/ml ≈ 0.167 g/ml.

• Calculate the sugar concentration in vessel B: 40 g / 280 ml = 1/7 g/ml ≈ 0.143 g/ml.

• Calculate the sugar concentration in vessel C: 20 g / 100 ml = 1/5 g/ml = 0.200 g/ml.

• Compare the concentrations: Vessel C (0.200 g/ml) > Vessel A (0.167 g/ml) > Vessel B (0.143 g/ml).

• Since the concentration in vessel B is lower than in vessel C, the solution in B is less sweet than in C.

• Therefore, option (d) is the correct answer.

Why the other options are wrong

(a) sweeter than that in C: Vessel B has a lower concentration (1/7 g/ml) than vessel C (1/5 g/ml), so it is not sweeter.
(b) sweeter than that in A: Vessel B has a lower concentration (1/7 g/ml) than vessel A (1/6 g/ml), so it is not sweeter.
(c) as sweet as that in C: The concentrations are different (1/7 g/ml vs 1/5 g/ml), so they are not equally sweet.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2016, held on 7 August 2016. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.