6.6 Fraudulent Trader
Fraudulent trader questions involve purchasing or selling, less or more quantity than that has been promised. The approach for these questions is as follows.
1) Find the CP per
stated unit and SP per
stated unit. These stated values are the amounts that the trader promises to buy/sell at.
2) Find the CP per
actual unit and SP per
actual unit. These actual values provide the
actual Profit %.
Example 15
Ramlal purchases rice at Rs. 2.47 per kg and marks up the price by 17% and sells it. He uses a defective weighing machine while selling the rice. It measures 900 gm of rice as 1 kg. What is Ramlal's profit percentage?
Solution
Note that we need to find the answer in percentage terms and 2.47 is a difficult number. We need not use it as we are required to find the profit % and not the profit in Rupees.
∴ Let CP = Rs. 100 per 1 kg
SP per stated unit =100×1.17= Rs. 117 per 1 kg
Due to the faulty weighing machine, trader actually sells 0.9 kg instead of 1 kg.
SP per actual unit = Rs. 117 per 0.9 kg
=0.9kgRs.117=1kgRs.130= Rs. 130 per 1 kg
We need to use the actual CP and SP to find profit %.
Profit %=CPSP−CP×100%=100130−100×100%=30%
Answer: 30%
Example 16
Jairaman claims to purchase and sell Jowar at the same price per kg. However, he uses a defective pan balance, wherein, 1 side weighs 200 grams more than the other. He uses a 1 kg weight for every purchase and sale, and he uses the balance to his advantage while buying and selling. What is his actual profit %?
Solution
Let the CP and SP be Rs. 100 per kg. It is given that one side of the pan balance weighs 0.2 kg more than the other and he use the balance to his advantage.
While purchasing he would use the balance to his advantage by buying more, i.e., buy 1.2 kgs instead of the stated 1 kg.
Stated CP = Rs. 100 per 1 kg
Actual CP = Rs. 100 per 1.2 kg =1.2kgRs.100
=Rs.3250 per 1 kg
While selling he would sell less, i.e., sell 0.8 kgs instead of the stated 1 kg.
Stated SP = Rs. 100 per 1 kg
Actual SP = Rs. 100 per 0.8 kg =0.8kgRs.100
= Rs. 125 per 1 kg
Profit %=3250125−3250×100%=50%
Answer: 50%