Profit and Loss – Multiple layers of pricing tricks: A dishonest trader marks goods up by 80%, gives a 25% discount to customers, gets 20% extra quantity per kg from his wholesaler, and sells 10% less per kg to customers. What is his overall profit percentage?

Introduction / Context:
This combines price manipulation (markup and discount) with quantity manipulation (extra when buying and short when selling). To handle this cleanly, compute everything per true kilogram. Determine cost per true kg and revenue per true kg, then compare.

Given Data / Assumptions:

• Markup = +80% ⇒ MP = 1.80 * nominal CP per labeled kg (call it P)
• Discount = 25% ⇒ SP per labeled kg = 0.75 * 1.80 * P = 1.35 * P
• Buys 20% extra ⇒ cost per true kg = P / 1.20
• Sells 10% less per labeled kg ⇒ delivers 0.90 true kg per labeled kg

Concept / Approach:
Cost per labeled kg delivered (0.90 true kg) = 0.90 * (P / 1.20) = 0.75 P. Revenue per labeled kg = 1.35 P. Profit% = (1.35 P − 0.75 P) / (0.75 P) * 100.

Step-by-Step Solution:
Cost per labeled kg delivered = 0.75 PRevenue per labeled kg = 1.35 PProfit = 1.35 P − 0.75 P = 0.60 PProfit% = 0.60 P / 0.75 P * 100 = 80%

Verification / Alternative check:
Compute per true kg instead; the ratio remains the same and confirms 80%.

Why Other Options Are Wrong:
60% and 70% underestimate the combined effect; 40% is too low; “None” is incorrect.

Common Pitfalls:
Adding or subtracting percentages without translating them into multiplicative factors and aligning per-true-unit calculations.

Final Answer:
80%