EP: You forgot something!
90 / 40 =2.25 - 1 x 100 =125%. Remember 100% of 40 is 80 and the 25% is that extra 10 + 80 = 90.
Dragan: If you have $40 and your dad gives you another $40 thereby doubling it, what is the percentage increase? 100% or 200%?
The question does not ask what percent increase is it from 40 to 90.....
it asks what percentage is 90 of 40.....
100% of 40 is 40
200% of 40 is 80
225% of 40 is 90