Question

By selling a book for Rs. 515, Gopal made a profit of Rs. 23. Find the cost of the book.

Answer 1

Hint: When profit is made, the selling price is greater than the cost price. The amount by which the selling price exceeds the cost price is called profit. Therefore, to find the cost price of the book, we can subtract profit from the selling price.
Formula used:

Complete step-by-step answer:
If cost price and profit was given and we would have been asked to find selling, then the sum of profit and cost price would give us the selling price.
If loss would have been provided in the question in place of profit, then cost price would have been calculated by adding selling price and loss. Here, the calculated cost price would have been greater than the given selling price.
If we would have been asked to calculate profit percentage, we could use the following formula:
\[\dfrac{\text{profit}}{\text{CP}}\times 100\]
Cost price is given by,
\[\text{CP = SP}-\text{profit}\]
Given,
SP = Rs. 515
Profit = Rs. 23
Cost of the book is calculated as:
$ \text{CP = SP}-\text{profit} $
$ \text{CP}=515-23 $
$ \text{CP}=\text{Rs}\text{. }492 $
Therefore, the cost of the book is Rs. 492.

Note: Since profit is only made when the selling price is greater than the cost price, the calculated cost price will always be less than the given selling price. We can also verify our answer by subtracting the cost price from the selling price. If the difference is equal to the given profit, the answer is correct.