1. How Do I Calculate Weight Loss in Percentage?
Answer: Divide the weight lost by the original weight, then multiply by 100 to find the percentage of weight lost.
Formula:
Weight Loss % = Weight Lost × 100\Original Weight
Example: Lost 5 kg from 70 kg → (5÷70) × 100 = 7.14%
2. How do I Calculate Percentage off a Price?
Answer: Multiply the original price by the discount percentage, then subtract the result from the original price to find the reduced amount.
Formula:
Discounted Price = Original Price − (Original Price × Discount%\100)
Example: 20% off on $100 → 100 − (100×0.2) = $80
3. How is Winning Percentage Calculated?
Answer: Divide the number of wins by total games played, then multiply by 100 to find the winning percentage.
Formula:
Winning % = Wins × 100\Total Games
Example: 8 wins out of 10 → (8÷10) × 100 = 80%
4. How Do You Calculate Average From Percentages?
Answer: Add all percentages, then divide the sum by the number of values to find the average percentage.
Formula:
Average % = ∑ Percentages\Number of Percentages
Example: (70%, 80%, 90%) → (70+80+90)÷3 = 80%
5. How is Percentage Error Calculated?
Answer: Subtract the true value from the measured value, divide the difference by the true value, then multiply by 100.
Formula:
Percentage Error = ∣Measured − True∣ ×100 \ True
Example: Measured = 98, True = 100 → ∣98−100∣ ÷ 100 × 100 = 2%
6. How do you calculate average for percentages?
Answer: Add the given percentages and divide by the total count to get the average percentage.
Formula:
Average % = ∑Percentages\Count
Example: (50%, 60%, 70%) → (50+60+70) ÷ 3 = 60%
7. How do you calculate percentage by mass?
Answer: Divide the mass of the solute by the total mass of the solution, then multiply by 100.
Formula:
Mass % = Mass of Solute × 100\Total Mass of Solution
Example: 5 g salt in 100 g solution → (5÷100) × 100 = 5%
8. How do you calculate the original amount from a percentage?
Answer: Divide the final amount by (1 – discount rate) or (1 + increase rate) to get the original amount.
Formula:
Original Price = Final Price\1 − Discount%\100
Example: $80 after 20% discount → 80 ÷ 0.8
9. How do you calculate percentage uncertainty?
Answer: Divide the absolute uncertainty by the measured value, then multiply by 100 to express it as a percentage.
Formula:
Percentage Uncertainty = Absolute Uncertainty × 100 \ Percentage Uncertainty
Example:
If the absolute uncertainty is 2g and the measured value is 50g:
2 × 100\50 = 4%
10. How do you calculate a variance percentage?
Answer: Divide the variance by the mean, then multiply by 100 to get the variance percentage.
Formula:
Variance Percentage = Variance × 100\Mean
Example:
If the variance is 16 and the mean is 200:
16 × 100\200 = 8%