A 20% reduction in the price of sugar enables a housewife to buy 6 kg more for Rs 240. Find the original price per kilogram.

Introduction:
Price reduction with fixed budget increases quantity purchased. Setting up quantities before and after the reduction yields a simple linear equation in the original price per kilogram.

Given Data / Assumptions:

• Budget = Rs 240
• Original price = x rupees/kg
• New price after 20% cut = 0.8x
• Increase in quantity = 6 kg

Concept / Approach:
Quantity before = 240/x. Quantity after = 240/(0.8x) = 300/x. The difference equals 6, giving an equation in x.

Step-by-Step Solution:
300/x − 240/x = 660/x = 6 ⇒ x = 10Original price = Rs 10 per kg

Verification / Alternative check:
At Rs 10/kg, old quantity = 24 kg; new price = Rs 8/kg → new quantity = 30 kg; increase = 6 kg (consistent).

Why Other Options Are Wrong:
8/6/5: These give differences not equal to 6 kg with the given budget.

Common Pitfalls:
Applying 20% to quantity or budget rather than price; arithmetic slips with proportions.

Final Answer:
Rs. 10 per kg