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Question

The selling price of 40 books is equal to the cost price of 28 books. Find the loss or gain percentage.

This question was previously asked in
RRB NTPC 2024 CBT 1 Question Paper (28-Aug-2025) (Shift 3)
The correct answer is
$30\% \text{ loss}$

Selling Price vs Cost Price Analysis

Let $C$ represent the cost price of one book and $S$ represent the selling price of one book.

The problem states that the selling price (SP) of 40 books is equal to the cost price (CP) of 28 books.

This can be written as an equation:

$ 40 \times S = 28 \times C $

Calculating the Loss Percentage

From the equation, we can find the relationship between $S$ and $C$:

$ S = \frac{28}{40} C $

Simplify the fraction:

$ S = \frac{7}{10} C $

Since the selling price ($S$) is $\frac{7}{10}$ of the cost price ($C$), it means $S < C$. This indicates a loss.

The loss amount for one book is:

$ \text{Loss} = C - S = C - \frac{7}{10} C = \frac{10C - 7C}{10} = \frac{3}{10} C $

To find the loss percentage, we use the formula:

$ \text{Loss Percentage} = \left( \frac{\text{Loss}}{\text{Cost Price}} \right) \times 100 $

Substitute the values:

$ \text{Loss Percentage} = \left( \frac{\frac{3}{10} C}{C} \right) \times 100 $

$ \text{Loss Percentage} = \frac{3}{10} \times 100 $

$ \text{Loss Percentage} = 30\% $

Therefore, there is a loss of 30%.

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Similar Questions

  1. I bought two frocks for ₹1,200. I sold the first one at a loss of 7% and the second at a gain of 23%. If, on the whole I made neither a loss nor a gain, find the cost price (in ₹) of the first frock.
  2. I bought two toy guns for ₹1,200. I sold the first one at a loss of 8% and the second at a gain of 16%. If, on the whole I made neither a loss nor a gain, find the cost price (in ₹) of the first toy gun.
  3. By selling $50$ mangoes for $₹30$, a person loses $10\%$. How many mangoes should he sell for $₹28$ to gain $20\%$?
  4. Sarita buys two old Samsung and three Mi mobile phones for ₹40,200. If she sells the Samsung phones at a 10% profit and the Mi phones at a 20% profit then her total profit is ₹5,640. The cost price of the Mi phone is:
  5. The cost price of 19 pens is equal to the selling price of 16 pens. Percentage gain is:
  6. X purchased a car at ₹ 1,50,000 and then sold it to Y at a profit of 5%. Y later sold it back to X at a loss of 2%. Find the overall profit or loss for X in the entire transaction
  7. The cost price of a car was ₹1,50,000. It was sold by X at a profit of 5% to Y. It was later sold back to X by Y at a 1% loss. Find X's profit in the entire transaction.
  8. A vendor sells 10 oranges for ₹1 and gains $30\%$. How many oranges did he buy for ₹1?
  9. Sohan lost $20\%$ by selling his old fan for ₹1,500. At what price (in ₹) he should have sold it to get $20\%$ profit?
  10. Find percentage loss when cost price = ₹850 and selling price = ₹680.

Important Questions from Profit and Loss

  1. By selling an article for Rs. 2,200, a profit of 10% is earned. If the same article is sold for Rs. 2,600, then what will be the gain percentage?

  2. By selling an article for Rs. 640, a person loses 15% of its selling price. At what price (in Rs.) should he sell it to gain 15% on its cost price?

  3. The selling prices of articles A and B are the same. A is sold at a profit of 28 percent and B is sold at a loss of 24 percent. If the total selling price of the both articles is Rs. 48640, then what is the cost price of A and B, respectively ?

  4. The cost price of an article is Rs. 2800. Profit as a percentage of selling price is 20 percent. What is the actual profit (in Rs.) ?

  5. A trader bought 640 kg of rice. He sold a part of rice at 20% profit and the rest at 5% loss. He earned a profit of 15% in the entire transaction. What is the quantity (in kg) of rice that he sold at 5% loss?

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