Lecture Notes: Calculating Original Price after Discount

Key Concepts

• Discount and Sale Price Relationship: Understanding how the original price, discount, and sale price are related.
• Formula Setup: Establishing the formula to calculate the original price of an item after a discount.

Steps to Calculate Original Price

1. Identify Sale Price

   • Sale price after discount: $479.20

2. Understand Discount Calculation

   • The TV is sold at a 20% discount.
   • Formula: Original Price - Discount = Sale Price
   • Discount is calculated as 20% of the original price.

3. Convert Percentage to Decimal

   • Convert 20% to a decimal for calculation: 0.20
   • Calculation is made against the original price.

4. Setup the Equation

   • Let the original price be 'x'.
   • Equation: x - 0.20x = 479.20
   • Simplify: 0.80x = 479.20
   • Understanding: Subtracting 0.20x (20%) from x results in 0.80x (80% of original price).

5. Solve for Original Price

   • To find 'x', divide the sale price by 0.80:
     • x = 479.20 / 0.80
   • Use a calculator for accuracy.
   • Result: x = $599.00

Conclusion

• The original price of the TV was $599.00 before the 20% discount was applied, resulting in a sale price of $479.20.