He got a 5% raise, so 28,140 is 105% of what it used to be.
105% means 1.05
(1.05) x (salary before increase) = 28,140
Divide each side by 1.05 :
Salary before increase = 28,140 / 1.05 = 26,800 .
The rest of the question is nonsense. The salary
before increase IS last year's salary.
