To solve this problem:
The formula would be: New Value – Old Value)/Old Value] x 100 or in the form of variable it would be: [(B-A)/A] x 100 = Answer.
So plugging in the information given in our problem it would be:
6 – 40 / 40 x 100 = percent of change
6/40 x 100 = 15%
The answer is $15