Input: There is a 50% increase from 80 to 120. To calculate this percentage change, we can use the following formula:

Percentage change = (new value - old value) / old value x 100%

In this case, the new value is 120 and the old value is 80. Plugging these values into the formula, we get:

Percentage change = (120 - 80) / 80 x 100%

Percentage change = 40 / 80 x 100%

Percentage change = 0.5 x 100%

Percentage change = 50%

Therefore, there is a 50% increase from 80 to 120. This means that the new value (120) is 50% greater than the old value (80). To check this, we can calculate the actual increase:

Actual increase = new value - old value

Actual increase = 120 - 80

Actual increase = 40

We can see that the actual increase is indeed 40, which is 50% of the old value (80).