Q. As a result of 25% hike in the price of rice per kg, a person is able to purchase 6 kg less rice for Rs. 1,200. What was the original price of rice per kg?
(a) Rs. 30
(b) Rs. 40
(c) Rs. 50
(d) Rs. 60
Correct Answer: (b) Rs. 40
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
Finding original price of rice
Let’s say the original price of rice per kg was x rupees. After a 25% hike in price, the new price would be 1.25x rupees per kg.
With Rs. 1,200, the person could originally buy (1200/x) kg of rice. After the price hike, they could only buy (1200/1.25x) kg of rice.
The difference between these two quantities is 6 kg: (1200/x) – (1200/1.25x) = 6.
Solving this equation for x, we get: x = 40.
So the original price of rice per kg was indeed Rs. 40.
