Answer:
The mistake was that 128% is equivalent to 1.28 times last year's profit not 12.8 times
Explanation:
we know that

Let
x -----> a company’s profits last year
y ----> a company’s profits this year
The company’s profits this year is equal to the company’s profits last year multiplied by 1.28
so

therefore
A company’s profits this year is 1.28 times last year’s profits
The mistake was that 128% is equivalent to 1.28 times last year's profit not 12.8 times