Pls make sure ur answer is correct

In 1985, there were 20 students

In 2005, there were 45 students

This is a change of 45-20 = 25 students.

This amount of change is divided by the original amount 20 to get 25/20 = 1.25 and converts to 125% when you move the decimal point 2 spots to the right.

If you want, you can use the formula below

x = old value = 20

y = new value = 45

z = percent change

z = [ (y-x)/x ] * 100%

z = [ (45-20)/20 ] * 100%

z = (25/20) * 100%

z = 1.25*100%

z = 125%

The z value being positive means we have a percent increase.

It's possible to have over 100% increase since 100% of 20 is 20. Having a 100% increase means we increased by 20. Since we increased by more than 20, this means the increase must be over 100%.