2015 CSAT, all questions
UPSC Prelims 2015 · CSAT
Question 77: Basic Numeracy
A cow costs more than 4 goats but less than 5 goats. If a goat costs between ₹ 600 and ₹ 800, which of the following is a most valid conclusion ?
aA cow costs more than ₹ 2,500.
bA cow costs less than ₹ 3,600.
cA cow costs between ₹ 2,600 and ₹ 3,800.
dA cow costs between ₹ 2,400 and ₹ 4,000.
AnswerUPSC’s answer is (d).
The goat price is between ₹600 and ₹800. The cow costs more than 4 goats: more than 4 × 600 = ₹2,400 at the lowest. It costs less than 5 goats: less than 5 × 800 = ₹4,000 at the highest. So the cow's price lies between ₹2,400 and ₹4,000. No tighter limit is certain, since the goat price could be anywhere in its range.
Why each option is right or wrong
- (a) Wrong: the cow could be just above 2,400, so 'more than 2,500' is not certain.
- (b) Wrong: the cow could be close to 4,000, so 'less than 3,600' is not certain.
- (c) Wrong: neither 2,600 nor 3,800 is a certain bound, as the range extends beyond both.
- (d) Right: the bounds 4 × 600 and 5 × 800 are the outer limits.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2015, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.