Q. 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
(c) 220 km
(d) 240 km
UPSC Prelims 2025 CSAT
Explanation :
1. Calculate the new price of petrol after a 10% hike:
New price = ₹90 × (1 + 10/100) = ₹90 × 1.10 = ₹99 per litre.
2. Find his original monthly fuel consumption:
Distance = 2200 km, Mileage = 16 km/litre
Fuel used = 2200 ÷ 16 = 137.5 litres.
3. Compute his original monthly expenditure:
Expenditure = 137.5 litres × ₹90 = ₹12 375.
4. Determine how much fuel he can buy at the new price to keep the same ₹12 375 spending:
Let allowed fuel = L litres.
L × ₹99 = ₹12 375
L = 12 375 ÷ 99 = 125 litres.
5. Find the distance he can travel with 125 litres at 16 km/l:
Distance = 125 × 16 = 2000 km.
6. Calculate the reduction in travel to maintain the same expenditure:
Reduction = Original distance – New distance
= 2200 km – 2000 km
= 200 km.
Therefore, he must cut his monthly travel by 200 km.