2020 CSAT, all questions
UPSC Prelims 2020 · CSAT
Question 70: Basic Numeracy
As a result of 25% hike in the price of rice per kg, a person is able to purchase 6 kg less rice for ₹ 1,200. What was the original price of rice per kg?
a₹ 30
b₹ 40
c₹ 50
d₹ 60
AnswerUPSC’s answer is (b).
Let the original price be ₹p per kg. For ₹1,200 he first buys 1,200/p kg, and after a 25% hike he buys 1,200/(1.25p) = 960/p kg. The difference is 240/p = 6, so p = 40. Check: 1,200 / 40 = 30 kg; at ₹50 he gets 24 kg; the difference is 6 kg.
Why each option is right or wrong
- (a) At 30, 40 kg falls to 32 kg, a difference of 8 kg.
- (b) Right: 30 kg falls to 24 kg.
- (c) At 50, 24 kg falls to 19.2 kg.
- (d) At 60, 20 kg falls to 16 kg, a difference of 4 kg.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2020, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.