Calculating the Original Price of a Book After a Discount

Calculating the Original Price of a Book After a Discount

When dealing with discounts, it’s common to need to find the original price given the final price and the discount percentage. In this article, we will delve into a detailed explanation of how to calculate the original price of a book after it has been discounted. We will use two different methods to solve this problem, ensuring that you can understand and apply the math effectively.

Method One: Algebraic Approach

Let's assume the original price of a book to be X PHP (Philippine Peso). The book is sold at a discount of 33.5%, meaning it is sold at 66.5% (100% - 33.5%) of its original price. This can be expressed as:

66.5%

66.5% of the original price is equal to the final price.

Mathematically, this is expressed as:

0.665X 230

To solve for X, we rearrange the equation:

X 230 / 0.665

X 346.79, which we can round to 347 PHP (to the nearest whole number).

Let's verify the solution:

347 PHP * 33.5% 347 * 0.335 116.395 PHP disc

347 PHP - 116.395 PHP 230.605 PHP ≈ 230 PHP

The slight variation is due to rounding.

Method Two: Direct Calculation

The second method can be more straightforward. If the final price after a 33.5% discount is 230 pesos, we can work backwards to find the original price using the following steps:

Let’s assume the final price (230 PHP) is 66.5% of the original price (100% - 33.5%). We can express this as:

66.5% 230

1% 230 / 66.5 ≈ 3.46 PHP

100% (original price) 3.46 PHP * 100 ≈ 346 PHP

Thus, the original price of the book is 346 PHP.

Verifying the solution:

346 PHP * 33.5% 346 * 0.335 116.39 PHP disc

346 PHP - 116.39 PHP 230 PHP

This confirms that the original price is indeed 346 PHP.

Conclusion

Both methods yield the same result. The original price of the book, after a 33.5% discount, is 346 PHP (or approx. 347 PHP to the nearest whole number).

Additional Notes

If you were to round 33.5% to 33.333333333333333... (i.e., 33 1/3%), the calculation would be different due to the exact nature of the discount factor. In such a case, 230 pesos would represent 2/3 of the original price, leading to an original price of 345 PHP (since 2/3 of 345 is exactly 230).

Understanding these methods can be very useful in various scenarios, such as competitive exams, real-world business transactions, or personal finance management.