An article yields Rs 6 more when sold at a 12% gain than when sold at a 12% loss. Determine the cost price of the article.

Introduction:
When two selling scenarios differ only by the sign of the percentage (gain versus loss) on the same cost price, the difference of the two selling prices is twice the percentage factor times the cost price. This leads quickly to the cost price.

Given Data / Assumptions:

• Gain scenario: SP1 = 1.12 * CP.
• Loss scenario: SP2 = 0.88 * CP.
• SP1 - SP2 = Rs 6.

Concept / Approach:
Subtract the two expressions to eliminate CP scaling: (1.12 - 0.88) * CP = 0.24 * CP = 6. Solve for CP.

Step-by-Step Solution:
SP1 - SP2 = (1.12 - 0.88) * CP0.24 * CP = 6CP = 6 / 0.24 = 25

Verification / Alternative check:
Check with CP = 25: SP at 12% gain = 28; SP at 12% loss = 22; difference = 6, confirming the calculation.

Why Other Options Are Wrong:

• Rs. 20, Rs. 24, Rs. 30: do not satisfy the difference of 6 when applying ±12%.

Common Pitfalls:

• Using 12% of SP rather than CP.
• Forgetting that the two percentages are applied to the same base.

Final Answer:
Rs. 25