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Question

A shopkeeper cheats to the extent of $10\%$ while buying as well as while selling. While he was eventually caught and punished, at what percent was he gaining till then?

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is

$21\%$

Shopkeeper Gain Calculation

This problem requires calculating the total percentage gain made by a shopkeeper who employs cheating tactics both when buying goods and when selling them.

Analyzing Cheating Percentages

The shopkeeper cheats by $10\%$ while buying and by $10\%$ while selling.

Gain on Buying

When cheating on buying, the shopkeeper effectively gets more value for the money spent. If he spends $₹100$, he receives goods worth $₹100 \times (1 + \frac{10}{100}) = ₹110$. This implies his effective cost price is lower relative to the value received.

Gain on Selling

When cheating on selling, the shopkeeper increases his revenue. If he sells goods worth $₹110$ (the value he acquired), he charges the price for $₹110 \times (1 + \frac{10}{100}) = ₹121$. This means his selling price is higher than the value of goods delivered.

Calculating Net Profit Percentage

To determine the overall gain, let's assume the shopkeeper starts with an initial investment.

  • Let the initial amount spent (Cost Price, $CP$) be $₹100$.
  • Due to the $10\%$ cheating on buying, the value of goods obtained for $₹100$ is $₹110$.
  • The shopkeeper then sells these goods. Due to the $10\%$ cheating on selling, the revenue generated from selling $₹110$ worth of goods is $₹110 \times (1 + \frac{10}{100}) = ₹121$. This is the Selling Price ($SP$).
  • The total profit is the difference between the Selling Price and the initial Cost Price:

$ \text{Profit} = SP - CP = ₹121 - ₹100 = ₹21 $

  • The profit percentage is calculated with respect to the initial Cost Price ($CP$):

$ \text{Profit Percentage} = \left( \frac{\text{Profit}}{CP} \right) \times 100 $

$ \text{Profit Percentage} = \left( \frac{₹21}{₹100} \right) \times 100 = 21\% $

Formula Method for Net Gain

A direct formula can be used for successive percentage gains:

$ \text{Net Gain \%} = \left( x + y + \frac{xy}{100} \right) \% $

Here, $x$ represents the percentage gain on buying ($10\%$) and $y$ represents the percentage gain on selling ($10\%$).

Substituting the values:

$ \text{Net Gain \%} = \left( 10 + 10 + \frac{10 \times 10}{100} \right) \% $

$ \text{Net Gain \%} = \left( 20 + \frac{100}{100} \right) \% = (20 + 1) \% = 21\% $

Thus, the shopkeeper was gaining at a total rate of 21%.

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Similar Questions

  1. A vendor claims to sell wheat at a loss of 50%, but he cheats by using weights that are 65% less than the stated weight. What is his actual profit percentage (round off to two decimal places)?
  2. Newton is the unit to measure _____.
  3. A man sells flowers at 4% loss on cost of price but he uses 20g instead of 25g weight to measure. What is his percentage profit?
  4. A trader sells rice, claiming 1 kg but actually gives x grams. He marks the price 20% above the cost price and gives a 10% discount on the marked price. If his overall profit is 25%, find x.

  5. A dishonest shopkeeper professes to sell his goods at a 35% loss but uses a false balance and gains 85%. The actual weight (rounded off to one decimal place) he uses for 1 kg is:

  6. A merchant buys tea at ₹100 per kg and sells it using a 800 g weight as 1 kg, after marking the price up by 25% and giving a discount of 20%. What is his profit per kg?

  7. A shopkeeper marks the price of sugar 24% above the cost price and gives a discount of 18%, but uses a weight of 800 grams instead of 1 kg. Find his overall profit percentage.

  8. A shopkeeper purchases rice at ₹60 per kg. While selling, he uses a weighing scale that shows 1 kg when only 900 g is actually weighed. He marks the price 20% above the cost price. Later, he gives a 10% discount on the marked price but continues using the same faulty scale. Find his profit (in ₹) on each transaction where the buyer pays for 1 kg.

  9. A shopkeeper buys sugar at ₹48 per kg. While selling, he uses a faulty weighing scale that gives only 960 g instead of 1 kg. In addition, he marks the selling price at a profit of 20% on the cost price and then offers a discount of 10% on the marked price. Find the overall percentage profit or loss made by the shopkeeper.

  10. A shopkeeper claims to sell rice at cost price, but uses a false weight and gains 25%. For 1 kg, how much rice does he actually give?


Important Questions from Dishonest Dealings

  1. A merchant claims that he sells his goods at CP. But uses a weight of 900 g for the 1 kg weight. find his gain %

  2. A shopkeeper cheats to the extent of 9% while buying and selling fruits, by using tampered weights. His total gain in percentage is:

    A. 18.25

    B. 18.81

    C. 19.78

    D. 18.5

  3. What is the faulty weight used by a dishonest shopkeeper instead of the original weight of 1 kg to get a profit of 25%?

  4. A dishonest financier claims to be lending money at simple interest, but he includes the interest every four months for calculating the principal. If he is charging an interest of 3%, the effective rate of interest becomes:

  5. A dishonest shopkeeper claims to sell rice at the cost price of ₹95 per kg, but the weight he uses has 1 kg written on it, while it actually weighs 950 g. The profit he thus earns on selling rice having an actual weight of 95 kg rice is:

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