How do you calculate the percentage increase from 40 to 50?

To calculate the percentage increase from one value to another, we use the formula:

[

\text{Percentage Increase} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100

]

In this scenario, the old value is 40 and the new value is 50. Plugging these into the formula gives:

[

\text{Percentage Increase} = \frac{50 - 40}{40} \times 100

]

This correctly follows the formula by determining the difference between the new and old values, which is 10 in this case, and then dividing that difference by the old value (40). This fraction is then multiplied by 100 to convert it into a percentage, resulting in a percentage increase of 25%.

The other methods of calculating percentage increase provided in the incorrect options either use the wrong denominator, calculate the difference without converting it into a percentage, or perform calculations inappropriately, which may lead to misleading results. This makes the correct calculation crucial for understanding the actual growth in relation to the initial value.