A trader buys from a wholesaler whose balance reads 1200 g for what is truly 1000 g (over-reading scale). The trader then marks up goods by 20% above his cost and sells to customers (use a correct scale). Determine the trader’s overall profit or loss percentage.

Introduction:
Faulty weights affect the actual quantity received for a given billed weight. If a wholesaler’s scale over-reads, the buyer receives less than billed. We must combine this effect with the retailer’s 20% markup to find the net outcome.

Given Data / Assumptions:

• Wholesaler’s reading 1200 g corresponds to true 1000 g (over-reading by factor 1.2).
• Retailer pays per “kg” by reading, but actually receives only 5/6 kg true per billed kg.
• Retailer uses a correct scale for selling and marks up 20% on his cost per kg.

Concept / Approach:
Per billed kg at cost C, true quantity received = 5/6 kg. If the retailer sets selling price at 20% above cost per kg, revenue per true kg = 1.2C. Multiply by true kg received to compare total revenue with total cost.

Step-by-Step Solution:
Cost for 1 billed kg = C; true quantity received = 5/6 kgRetailer’s SP per true kg = 1.2C (20% markup on cost)Revenue from that batch = (5/6) * 1.2C = CThus revenue equals cost ⇒ 0% net profit/loss

Verification / Alternative check:
Scaling the batch size or cost leaves the product (5/6 * 1.2) unchanged at 1.00, so the conclusion is robust.

Why Other Options Are Wrong:

• 38% / 50% profit: ignore the short-quantity factor canceling the 20% markup.
• None of the above: incorrect because 0% is exact.

Common Pitfalls:

• Assuming both wholesaler and retailer use faulty balances, which is not stated.

Final Answer:
no profit no loss