Mathematical Formula For Calculating Percentage Decrease
\[ \text{Percentage Decrease} = \frac{\text{Initial Value} – \text{New Value}}{\text{Initial Value}} \times 100 \]
Example Broken Down With Steps
$$
\text{Given: Initial Value = 500, New Value = 400}
$$
$$
\text{Step 1: Subtract 400 from 500: } 500 – 400 = 100
$$
$$
\text{Step 2: Divide 100 by 500: } \frac{100}{500} = 0.2
$$
$$
\text{Step 3: Multiply 0.2 by 100: } 0.2 \times 100 = 20
$$
$$
\text{Result: The price dropped by 20%.}
$$
Further Explained
Example: A book’s price dropped from 500 to 400.
Steps:
- Find the decrease in value: Subtract the new price from the original price:
$$ 500 – 400 = 100 $$ - Divide the decrease by the original price:
$$ \frac{100}{500} = 0.2 $$ - Convert to a percentage: Multiply the result by 100:
$$ 0.2 \times 100 = 20\% $$ - Conclusion: The price decreased by 20%.