Final answer:
Percentage increase refers to the proportional increase from an original amount expressed as a percent, while 'what percentage of' describes what portion one quantity is of another. To find percentage increase, the formula (Change/Original Quantity) × 100% is used, whereas for finding what percentage one number is of another, we use (Part/Total) × 100%.
Step-by-step explanation:
The difference between 'Percentage increase' and 'what percentage of' is that Percentage increase refers to how much something has increased in comparison to its original amount, expressed as a percent. For instance, if your pay increases from $10 to $12 per hour, the percentage increase is calculated as the change in quantity ($2) over the original quantity ($10), resulting in 0.20 or 20%.
On the other hand, when we ask 'what percentage of a total', we are looking for what portion a specific value represents out of the whole. For example, if you score 96 points out of 100 on a test, 96% is the percentage of points you achieved.
To get the percentage increase, we do not need to subtract 100. However, when calculating the percentage of one quantity relative to another and expressing it as a percent growth or decrease, we may end up subtracting 100 if we want to represent the proportional change from a base of 100%.