UPSC Prelims 2018 · CSAT
Question 69: Basic Numeracy
A person bought a refrigerator worth ₹22,800 with 12·5% interest compounded yearly. At the end of first year he paid ₹8,650 and at the end of second year ₹9,125. How much will he have to pay at the end of third year to clear the debt?
AnswerUPSC’s answer is (d).
Add 12.5% each year, then subtract the payment. Year 1: 22,800 × 1.125 = 25,650; less 8,650 leaves 17,000. Year 2: 17,000 × 1.125 = 19,125; less 9,125 leaves 10,000. Year 3: 10,000 × 1.125 = 11,250, which clears the debt. Interest must be added to the balance before each payment.
Why each option is right or wrong
- (a) 9,990 would not clear the debt, which stands at 11,250 with interest.
- (b) 10,000 is the balance after year two, before the third year's interest.
- (c) 10,590 does not match 10,000 × 1.125.
- (d) Correct: 10,000 × 1.125 = 11,250.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2018, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.