A trader allows a discount of 10% on the marked price. By what percentage above the cost price should the article be marked so that the trader still makes a 17% profit?

Introduction / Context:
We must connect the desired profit to the ultimate selling price after discount. The marked price must be set high enough so that a 10% discount still leaves a 17% margin on cost.

Given Data / Assumptions:

• Let cost price (CP) = C rupees.
• Desired profit = 17% on C ⇒ target SP = 1.17 * C.
• Discount on marked price (MP) = 10% ⇒ SP = 0.90 * MP.

Concept / Approach:
Equate the two expressions for SP to compute MP relative to C, then convert to the percentage markup required over C.

Step-by-Step Solution:
0.90 * MP = 1.17 * CMP = (1.17 / 0.90) * C = 1.30 * CThus, markup over cost = 30%.

Verification / Alternative check:
If C = 100, choose MP = 130; discount 10% → SP = 117; profit = 17 which is 17% of 100.

Why Other Options Are Wrong:
25%, 28%, 24%: Do not reconcile with SP = 117% of CP after a 10% reduction on MP.

Common Pitfalls:
Subtracting 10 from 17 directly; applying percentages on the wrong base (CP vs MP).

Final Answer:
30%