The petrol price shot up by 10% as a result of the hike in crude oil prices. The price of petrol before the hike was ₹ 90 per litre. A person travels 2200 km every month and his car gives a mileage of 16 km per litre. By how many km should he reduce his travel if he wants to maintain his expenditure at the previous level ?
- (a) 180 km
- (b) 200 km ✓ UPSC's answer
- (c) 220 km
- (d) 240 km
Why the answer is (b)
• The initial petrol price is ₹90 per litre, and the new price after a 10% hike is ₹90 + (10% of 90) = ₹99 per litre.
• The person's monthly travel distance is 2200 km with a mileage of 16 km/litre, requiring 2200 / 16 = 137.5 litres of petrol.
• The previous monthly expenditure was 137.5 litres × ₹90/litre = ₹12,375.
• To maintain the same expenditure of ₹12,375 at the new price of ₹99/litre, the maximum petrol he can buy is 12,375 / 99 = 125 litres.
• The distance he can travel with 125 litres at 16 km/litre is 125 × 16 = 2000 km.
• The reduction in travel distance is 2200 km - 2000 km = 200 km, which corresponds to option (b).
Why the other options are wrong
- (a) 180 km
- 180 km is incorrect because the calculated reduction is exactly 200 km, not 180 km.
- (c) 220 km
- 220 km is incorrect because the calculated reduction is exactly 200 km, not 220 km.
- (d) 240 km
- 240 km is incorrect because the calculated reduction is exactly 200 km, not 240 km.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.