You can
put this solution on YOUR website!The situation can be modelled as 2 linear equations
Let Salary,

, be plotted on the vertical axis
Let Years,

, be plotted on the horizontal axis (staring at zero)
For Sonja,
(1)

For Chris,
(2)

I can rewrite them as
(1)

(2)

I'll find out in what year Salaries are equal

Divide both sides by 28000

Their salaries will be equal in 20 years
Chris's will exceed Sonja's in 21 years,
or March 1st, 2022.
If you're sure the answer is 2014, then I made a
mistake, but I think the method is OK.
I'll plot them: