A dishonest dealer claims to sell a product at its cost price. He uses a false weight that is 20% less than the real weight, and he also mixes impurities equal to 10% of the weight of the product. Find the net profit percentage of the dealer.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 37.5%
The customer pays the cost price of 1 kg, but the dealer spends only on the real product he hands over. Profit % \(=\) (price received − cost of product given) ÷ cost of product given.
Let the cost price be Rs 1 per gram; the customer pays Rs 1000 for "1 kg"
False weight: he hands over only \(1000\times0.8=800\) g of the mixture
Impurity is 10% of the product, so product : mixture \(=100:110\)
Real product given \(\displaystyle =800\times\frac{100}{110}=\frac{8000}{11}\) g, costing Rs \(\frac{8000}{11}\)
Profit % \(\displaystyle =\frac{1000-\frac{8000}{11}}{\frac{8000}{11}}\times100=\frac{3000}{8000}\times100=37.5\%\)
The dealer’s net profit is 37.5%.