In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
Salary
last year = $392
this year = $431
the percent of the increase = ?
Step 02:
this year - last year = $431 - $392 = $39
percent of the increase = 9.95 %
The answer is:
The Maria's salary percent of the increase is 9.95%.