Hi, I believe the answer is In the last year, Paul earned $2,000 more.
Figuring out Paul's tenth year salary looks like this:
30,000 (base salary) + 10 (number of years) x 2,800 (yearly increase) should get you 58,000.
Figuring Sharla's tenth year salary looks like this:
36,000 (base salary) + 10 (number of years) x 2,000 (yearly increase) gets you 56,000.
58,000 - 56,000 is 2,000.
Hope this helps! :)