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?

1. A. 180 km
2. B. 200 km
3. C. 220 km
4. D. 240 km

Answer: B

Explanation

Let’s calculate the initial expenditure:
Initial petrol price = ₹90 per litre.
Monthly travel distance = 2200 km.
Car mileage = 16 km per litre.

Initial fuel consumption = Total distance / Mileage = 2200 km / 16 km/litre = 137.5 litres.
Initial monthly expenditure = Initial fuel consumption × Initial price = 137.5 litres × ₹90/litre = ₹12375.

Now, calculate the new petrol price:
Price hike = 10%.
New petrol price = ₹90 + (10% of ₹90) = ₹90 + ₹9 = ₹99 per litre.

The person wants to maintain the expenditure at the previous level, i.e., ₹12375.
New fuel consumption = Desired expenditure / New price = ₹12375 / ₹99/litre = 125 litres.

New travel distance = New fuel consumption × Mileage = 125 litres × 16 km/litre = 2000 km.

Reduction in travel distance = Initial travel distance – New travel distance
Reduction = 2200 km – 2000 km = 200 km.

This question tests practical application of percentages, ratios, and basic arithmetic in a real-world scenario, which is typical for UPSC CSAT quantitative aptitude.