So I got this problem

Original Amountis20the new amount is50

I need to find the percentage increase I usually use this method.

First find the increase from the original amount which is 30 (50-20)

Then 30/20 = 1.5

Then 1.5 * 100 = 150%

Now that does not seem to be the right answer as I check my answer by going vice versa how shall I do this?